We were on our way into town, speeding across the cold and brittle grasslands of New Mexico, when I heard about Santiago. Morales must have told me, or maybe it was Hart. I called Santiago as soon as I found out. You don’t have to quit, I told him, you can still finish, you should stay. I can’t, he said, it’s not the work for me. I should go back to Puerto Rico, I should be with my family. I wished him luck and told him I was sorry to see him go. He thanked me and said to finish for the both of us, and I promised I would.

Of all my classmates, it was Santiago I most wanted to see graduate. He marched out of step, his gear was a mess, he couldn’t handle his weapon, and it took him well over fifteen minutes to run the mile and a half. But he tried harder than any of us. He sweated the most, yelled the loudest. He was thirty-eight years old, an accountant from Puerto Rico, a husband and a recent father. The day before he quit, he left the firing range with a pocket full of live rounds and the instructors ordered him to sing “I’m a Little Teapot” in front of the class. He didn’t know the song, so they suggested “God Bless America.” He belted out the chorus at the top of his lungs, his chest heaving after each line as he gasped for air, thick with the smell of shit blowing in from the nearby dairy farms. We laughed, all of us, at his thick accent, at the misremembered verses, at his voice, off-key and quaking.

In town, over drinks, Hart went on about the winters in Detroit. I can’t go back there, he said, not like Santiago. Fuck that. He glared down at his beer and then looked up at us. You know what I did before this? he asked. Morales and I shook our heads. I was a clerk at a rent-a-car desk in the goddamned airport. You know how many times I handed car keys to people who wouldn’t even look me in the face? Guys who would glance at the tattoos on my arms like I was some thug, like I was some pathetic black kid part-timing outside the ghetto. Hart gripped his glass of beer. But more than any of that, I’m sick and tired of the winter.

Hart looked up from the table and mustered a smile. How about winter in Arizona? he asked. Morales laughed. You don’t have to worry about snow where we’re going, vato, that’s for sure. Hart thought it sounded nice. Sure, I said, but wait until the summer. Have you ever felt 115-degree heat? Hell no, Hart answered. Well, I told him, we’ll be out in it, fetching dead bodies from the desert. Hart looked puzzled. Who the fuck walks through the desert when it’s 115? he asked. I drank through the final gulp of another beer. Migrants used to cross in the city, I told him, in places like San Diego and El Paso, until the Border Patrol shut it all down in the nineties with fences and new recruits like us. Politicians thought if they sealed the cities, people wouldn’t risk crossing in the mountains and the deserts. But they were wrong, and now we’re the ones who get to deal with it. Hart lost interest in my rambling and attempted to flag down the server to order another beer. Morales stared at the table and then glanced up at me, his eyes dark and buried beneath his brow. Sorry for the lecture, I told them. I studied this shit in school.

On our way back to the academy, I sat in the backseat of Morales’s truck. In the front, Morales told Hart about growing up on the border in Douglas, about his uncles and cousins on the south side. Hart asked what kind of food they ate and Morales told him about hot bowls of menudo and birria in the morning, about the stands in Agua Prieta that sold tacos de tripa all through the night. Morales described how his mother made tortillas, how his grandmother prepared tamales at Christmastime, and I sat listening to his voice with my head against the cold glass of the window, staring at the darkened plain, slipping in and out of sleep.

Robles ordered us from the mat room into the spinning room and we each took our place atop a stationary bicycle. At the front of the room, Robles climbed atop a machine that had been situated to face us and shouted for us to begin pedaling. At no point should your legs stop moving, he yelled. When I say stand, lift your ass off the seat and keep it in the air until I tell you to sit. He snapped his head toward a stout man in the front row named Hanson. Is that clear, Mr. Hanson? Yes sir, Hanson shouted, already out of breath.

As the minutes passed, Robles prodded us to work harder—sit, he shouted, move those legs, stand. Your body is a tool, he announced, the most important one you have. A baton is nothing, a Taser is nothing, even your gun is nothing if you give up on your body when it becomes tired, if you can’t hold it together when every muscle cries out for you to quit. In the Border Patrol, Robles continued, you will be tested—I can promise you that. In my time, I have taken a life and I have saved a life. When I was brand-new to the field, like all of you will be, my journeyman and I jumped a group of El Sals in the lettuce fields outside Yuma. A man ran from us and I chased after him until I thought my legs would give out. I stumbled and tripped over dirt berms and rows of lettuce, but I kept chasing him until we came to the edge of a canal and the man turned to face me. He came at me before I could react and we went to the ground fighting. If I had given up, maybe the man would have killed me. But I didn’t. I grappled with him in the dirt until I knocked him over the edge of the canal into the water. The man couldn’t swim, none of them can, and so an hour later me and my journeyman fished his dead body out of the water at a buoy line.

Robles’s eyes seemed to detach from his surroundings, as if his gaze had turned inward. A year after that, he continued, I chased another man to the banks of the Colorado River. He ran out into the water and was swept away by the current like it was nothing. And I’ll tell you what I did. I swam into the river and I battled to keep him afloat even as I inhaled mouthfuls of water, even though I can’t remember ever having been more tired. I saved that man’s life, and still, there’s not a single day I don’t think about the one I took before it.

As Robles fell silent, we stood sweating over our bikes, our legs pedaling weakly. In the front row, Hanson dropped his head, his ass falling to the seat. Robles snapped his gaze from the middle of the room and turned his head toward Hanson. Get back up there, he roared. Don’t give up on me, Mr. Hanson. Do not give up.

As the sound of our labored breathing settled back over the room, I thought briefly of the man from El Salvador and wondered how the news of his death might have arrived to his family, floating in the air like a corpse in black water. At the front of the room I watched Robles standing tall atop his bicycle, sweat dripping from his brow as he thrust his shoulders downward with each stroke of his legs. I wondered at his unwavering exertion, if his body was still being driven to make good for the life he had seen blink out in the swift currents of the canal. I wondered if he thought of his body as a tool for destruction or as one of safekeeping. I wondered, too, about my body, about what sort of tool it was becoming.

Before we took to the range one afternoon, the firearms instructor gave the class a PowerPoint presentation in a darkened room. Agents arrested more than 700,000 aliens on the border last year, he told us. If you think that’s bad, when I first got to the field eight years ago, back in 2000, that number was over one and a half million. And I’m here to tell you that not everybody coming across that line is a good person looking for honest work.

Our instructor beamed images of drug war victims onto a screen, grisly photos of people killed by the cartels in Mexico. In one image, three heads floated in a massive ice chest. In another, a woman’s body lay discarded in the desert, her feet bound, a severed hand stuffed into her mouth. The instructor paused on an image of a cattle truck with twelve dead bodies stacked in the back, all of them blindfolded and shot execution-style. These twelve weren’t gangsters, he told us, they were migrants kidnapped and killed for some meager and meaningless ransom. The next image showed a group of Mexican policemen shot dead in the street, and then an image of a bloodied body slumped in a car seat—a newly elected mayor who had promised to clean up the drug violence in his town, shot dead on his first day in office.

This is what you’re up against, our instructor told us, this is what’s coming.

So far seven have quit, whittling our class down to forty-three. Sullivan left exactly one week after Santiago. I didn’t know him but his roommate said he complained a lot. Serra, one of only three women in the class, quit two days later and no one knew why. She kept to herself, everyone said. Golinski went next, taking indefinite medical leave for a hairline fracture around his left knee. When I saw him at the computer lab the night before he left, I asked him what he would do when he got back home. He looked at me as if he didn’t understand the question. I’ll wait for my knee to heal and come back to the academy, he told me. I’ve had two tours in Iraq—I know I can do this job.

Hanson quit after receiving a job offer from his hometown police department in Illinois. It pays almost as well, he told us, and I won’t have to move my wife and kids. On Hanson’s last day at the academy, Robles lined us up at the start of PT and had us stand shirtless while he measured our body fat percentage. Hanson stood next to me in formation and I saw for the first time the loose skin that hung from his waist. When Robles came to take his measurements he glanced at the extra skin and then up at Hanson’s face. How much weight did you lose? Robles asked. A hundred eighty pounds in a year and a half, Hanson said, staring straight ahead. Robles nodded. Let’s hope you never put it back on.

Dominguez, Hart’s roommate, was next to quit, dropping out after failing his third law test. For days I wondered if I could have done more to help him pass. One night Hart and I sat eating dinner together at a cafeteria table. Why didn’t you invite him to study with us? I asked. He was your roommate, you should have looked after him. Hart looked at me incredulously. Fuck you, he said, tossing his dinner roll onto his plate. Dominguez could have passed if he wanted to. He was too busy talking on the fucking phone all night. Listen, he said, Dominguez was smart enough to pass the U.S. citizenship test in high school and he was smart enough to earn a bachelor’s degree in construction management after that. You’re not the only one who went to college. Hell, he was even smart enough to run his own construction business before the housing market went to shit, did you know that? Hart picked the dinner roll off his plate and ripped off a bite. Instead of studying, he continued, Dominguez spent all his free time talking to his family, and it’s sure as hell not my fault or anyone else’s. I sat thinking for several moments. What did they talk about? I finally asked. Hart shrugged his shoulders. How should I know, he said, I don’t speak Spanish.

My mother flew in from Arizona to see me for Christmas. She picked me up from the academy on Christmas Eve and we drove through the straw-colored hills, leaving behind the trembling Chihuahuan grasslands as we climbed into evergreen mountains. We stayed the night in a two-room cabin, warm and bright with pinewood. We sat in chairs around the living room table, decorating a miniature tree with tiny glass bulbs. Then, wrapped in blankets, we laughed and drank eggnog with brandy until the conversation finally descended into a discussion of my impending work.

Listen, my mother said, I spent most of my career as a park ranger, so I’ve got nothing against you working for the government. But don’t you think it’s sort of below you, earning a degree just to become a border cop? When people ask about you back home and I tell them you’re in law enforcement, they give me the strangest looks. I realize I don’t know what more to tell them, I don’t really understand what you want from this work.

I took a deep breath. Look, I told her, I spent four years in college studying international relations and learning about the border through policy and history. You can tell whoever asks that I’m tired of studying, I’m tired of reading about the border in books. I want to be on the ground, out in the field, I want to see the realities of the border day in and day out. I know it might be ugly, I know it might be dangerous, but I don’t see any better way to truly understand the place.

My mother stared at me, blinking rapidly. Are you crazy? she asked. There are a hundred other ways of knowing a place. You grew up near the border, living with me in deserts and national parks. The border is in our blood, for Christ’s sake—your great-grandparents brought my father across from Mexico when he was just a little boy. When I married, I insisted on keeping my maiden name so that you’d always carry something from your grandfather’s family, so you’d never forget your heritage. How’s that for knowing the border?

I lowered my voice. I’m grateful for those things, I told her, but having a name isn’t the same as understanding a place. I gestured toward the window. I want to be outside. Not in a classroom, not in an office, not sitting at a computer, not staring at papers. Do you remember, I asked my mother, how you joined the Park Service because you wanted to be outdoors, because you felt you could understand yourself in wild places? My mother narrowed her eyes at me as if I had suddenly changed the subject. It’s not that different, I said. I don’t know if the border is a place for me to understand myself, but I know there’s something here I can’t look away from. Maybe it’s the desert, maybe it’s the closeness of life and death, maybe it’s the tension between the two cultures we carry inside us. Whatever it is, I’ll never understand it unless I’m close to it.

My mother shook her head. You make it sound like you’ll be communing with nature and having heartfelt conversations all day. The Border Patrol isn’t the Park Service. It’s a paramilitary police force. I glared at her. You don’t have to tell me that, I said—I’m the one getting my ass kicked at the academy.

Listen, I know you don’t want your only son turning into a heartless cop. I know you’re afraid the job will turn me into someone brutal and callous. Those people who look at you funny when you tell them I’m in the Border Patrol probably imagine an agency full of white racists out to kill and deport Mexicans. But that’s not me, and those aren’t the kind of people I see at the academy. Nearly half my classmates are Hispanic—some of them grew up speaking Spanish, some grew up right on the border. Some went to college, like me. Some went to war, some owned businesses, some worked dead-end jobs, some are fresh out of high school. Some are fathers and mothers with their own children. These people aren’t joining the Border Patrol to oppress others. They’re joining because it represents an opportunity for service, stability, financial security—

My mother interrupted me. But you could work anywhere you want, she said, you graduated with honors.

So what? I asked. This isn’t necessarily a lifelong career choice. Think of it as another part of my education. Imagine what I’ll learn—imagine the perspective I’ll gain. Look, I know you’re not an enforcement-minded person, but the reality of the border is one of enforcement. I might not agree with every aspect of U.S. border policy, but there is power in understanding the realities it creates. Maybe after three or four years I’ll go back to school to study law, maybe I’ll work to shape new policies. If I become an immigration lawyer or a policy maker, imagine the unique knowledge I’ll bring, imagine how much better I’ll be at the job because of my time in the Border Patrol.

My mother sighed and looked up at the ceiling. There are ways to learn these things that don’t put you at risk, she said, ways that let you help people instead of pitting you against them. But that’s just it, I offered—I can still help people. I speak both languages, I know both cultures. I’ve lived in Mexico and traveled all across the country. I’ve seen towns and villages that were emptied out by people going north for work. Good people will always be crossing the border, and whether I’m in the Border Patrol or not, agents will be out there arresting them. At least if I’m the one apprehending them, I can offer them some small comfort by speaking with them in their own language, by talking to them with knowledge of their home.

Fine, my mother said, fine. But you must understand you are stepping into a system, an institution with little regard for people.

I looked away from her and a silence hung between us. I glanced down at my hands and weighed my mother’s words. Maybe you’re right, I replied, but stepping into a system doesn’t mean that the system becomes you. As I spoke, doubts flickered through my mind. I smiled at my mother. The first job I ever had was bussing dishes with migrants from Guanajuato, I reminded her. I’m not going to lose sight of that. I’m not going to become someone else.

Good, my mother said. I hope you’re right.

We hugged, and my mother told me she loved me, that she was happy I’d soon be working back in Arizona, closer to her. Before bed, we each opened a single present, as we had done every Christmas Eve since I could remember.

In the morning we ate brunch at the town’s historic hotel, feasting on pot roast by a crackling fire. Afterward we climbed the stairs to a narrow lookout tower where people huddled together in jackets, walking in slow circles to take in the view. Below us, a sunlit basin stretched westward from the base of the mountains. I watched as the landscape shifted under the winter light. Behind me, my mother placed her hand on my shoulder and pointed to a cloud of gypsum sand in the distance, impossibly small, swirling across the desert below.

At graduation we stood before friends and loved ones in our campaign hats and full-dress uniforms with iron-creased pant legs and shirtsleeves, our boots and brass buckles polished to shine under the fluorescent light of the academy’s auditorium. Our instructors made speeches about the value of our training, about the importance of our pending duties. We received awards, badges were pinned to our chests. We stood side by side and turned to face our audience, holding up our right hands as we stared steely-eyed at the room’s pale walls. I do solemnly swear that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter. So help me God.

We caught our first dope load only two days after arriving at the station. We were east of the port of entry when a sensor hit, just three miles away. At the trailhead, Cole, our supervisor, pointed to a mess of footprints stamped in the dirt. He followed the prints up the trail and after several minutes motioned for us to pile out of the vehicles. We’ve got foot sign for eight, he told us, keep quiet and follow me.

For five miles we walked toward the mountains with Cole leading the way. He called us up one by one to watch us cut the sign. Keep your vision soft, he told us, scan the ground about five or six yards out. Try to cut with the sun in front of you, never at your back, so that the sign catches the light. If a trail gets hard to cut, look for small disturbances—toe digs, heel prints, kicked-over rocks, the shine of pressed-in dirt, fibers snagged on spines and branches. If you lose the sign, go back to where you last had it. Learn to read the dirt, he said, it’s your bread and butter.

We found the first bundle discarded among the boulders at the base of the pass. They must have seen us coming, Cole said. He directed us to spread out to comb the hillsides, and after ten minutes we had recovered two backpacks filled with food and clothes and four additional bundles wrapped in sugar sacks spray-painted black. Those ought to be about fifty pounds each, Cole told us. He kicked one of the bundles with his foot. Two hundred fifty pounds of dope—not bad for your second day in the field. I asked Cole if we should follow the foot sign up into the pass, if we should try to track down the backpackers. Hell no, he said, you don’t want to bring in any bodies with your dope if you can help it. Suspects mean you have a smuggling case on your hands, and that’s a hell of a lot of paperwork—we’d have to stay and work a double shift just to write it up. Besides, he said, the prosecutors won’t take it anyway. Courts here are flooded with cases like this. He smiled. Abandoned loads are easy though. You’ll see.

Cole had us dump the backpacks and I watched as several of my classmates ripped and tore at the clothing, scattering it among the tangled branches of mesquite and palo verde. In one of the backpacks I found a laminated prayer card depicting Saint Jude, a tongue of flames hovering above his head. Morales found a pack of cigarettes and sat smoking on a rock as others laughed loudly and stepped on a heap of food. Nearby, Hart giggled and shouted to us as he pissed on a pile of ransacked belongings.

As we hiked with the bundles back to our vehicles, the February sun grew low in the sky and cast a warm light over the desert. At the edge of the trail, in the pink shade of a palo verde, a desert tortoise raised itself on its front legs to watch us pass.

At night we stood for hours in the darkness along the pole line. After we had tired of the cold and the buzzing power lines, Cole had us lay a spike strip across the dirt road and return to wait in our vehicles, parked in a nearby wash. We sat with the engines on and the heat blasting, and after a few minutes of silence, Morales asked Cole why some of the agents at the station called him “Black Death.” Cole laughed and pulled a can of Copenhagen from his shirt pocket. You have to be careful, he said, the Indians out here, when they’re drunk and walking at night between the villages, they fall asleep on the fucking road. He packed the can as he spoke, swinging his right arm and thumping his forefinger across the lid. When it’s cold out, the asphalt holds warmth from the sun, even at night. A few years ago I was working the midnight shift, driving down IR-9, and I saw this fucking Indian asleep in the middle of the road. I stopped the truck and woke his ass up. His brother was there with him, sleeping in the bushes. They were drunk as hell. Cole pinched a wad of dip into his mouth. His lower lip bulged, catching the green light from the control panel. I gave the guys a ride into the next village, he said, dropped them off at their cousin’s place. Told them not to sleep on the goddamn road. He grabbed an empty Pepsi cup from the center console and spat. Maybe nine or ten months later, same fucking spot, I ran over the guy, killed him right there. Same fucking guy, asleep on the damn road. I never even saw him. After that, they started calling me Black Death. Cole laughed and spat into his cup and a few of us laughed with him, not knowing exactly what kind of laugh it was.

Just after midnight a blacked-out truck roared across the spikes and three of its tires went. We tore after it, speeding blindly through a cloud of dust until we realized the vehicle had turned. We doubled back to where the tire sign left the road and followed it until we came upon the truck abandoned at the foot of a hill. In the back of the truck we found two marijuana bundles and a .22 rifle. Cole sent us to scour the hillside with our flashlights, but we recovered only one other bundle. It’s a fucking gimme load, Cole said. I asked what he meant. It’s a goddamn distraction, that’s what. They’re waiting us out. But my classmates and I didn’t care—we were high from the chase. We drove the truck into a wash until it became stuck, and we slashed the unpopped tire, leaving it there with the lights on and the engine running. On the way back to the station I asked Cole what would happen to the truck. He told me he’d call the tribal police to seize the vehicle, but I knew he wouldn’t. Even if he did, they wouldn’t come for it. They wouldn’t want the paperwork either.

After sundown Cole sent Morales up a hill near the highway with a thermal reconnaissance camera. Let me borrow your beanie, vato, he said to me, it’s cold out. I handed it to him and stayed inside the vehicle with the others. An hour later Morales spotted a group of ten just east of mile marker five. We rushed out of the car and set out on foot as he guided us in on the radio, but by the time we got there the group had already scattered. We found them one by one, huddled in the brush and curled up around the trunks of palo verde trees and cholla cactus. Not one of them ran. We made them take off their shoelaces and empty their backpacks and we walked all ten of them single file back to the road. For a while I walked next to an older man who told me they were all from Michoacán. It’s beautiful there, I said. Yes, he replied, but there’s no work. You’ve been to Michoacán? he asked. I told him I had. Then you must have seen what it’s like to live in Mexico, he said. And now you see what it’s like for us at the border. We walked on, and then, after several minutes, he sighed deeply. Hay mucha desesperación, he told me, almost whispering. I tried to look at his face, but it was too dark.

At the station I processed the man for deportation. After I had taken his fingerprints he asked me if there was any work for him at the station. You don’t understand, I said, you’ve just got to wait here until the bus comes. They’ll take you to headquarters and then on to the border. You’ll be back in Mexico very soon. I understand, he assured me, I just want to know if there is something I can do while I wait, something to help. I can take out the trash or clean out the cells. I want to show you that I’m here to work, that I’m not a bad person. I’m not here to bring in drugs, I’m not here to do anything illegal. I want to work. I looked at him. I know that, I said.

Cole took us to a lay-up spot just off the highway where he had almost been run over by smugglers. He led us to a wide wash full of old blankets and discarded clothes and pieces of twine and empty cans of tuna and crushed water bottles. We climbed out of the wash and walked up to a nearby cactus, a tall and sprawling chain-fruit cholla, and Cole asked if any of us had hand sanitizer. Someone tossed him a small bottle and he emptied the gel on the black trunk of the cactus. He asked for a lighter and with it he lit the gel, then stepped back to watch the flames crawl up the trunk, crackling and popping as they engulfed the plant’s spiny arms. In the light from the fire, Cole packed his can of dip and took a pinch into his mouth. His bottom lip shone taut and smooth, his shaved black skin reflecting the light from the flames. He spat into the fire and the rest of us stood with him in a circle around the cholla as it burned, laughing and taking pictures and videos with our phones as thick smoke billowed into the night, filling the air with the resinous smell of hot asphalt.

Cole was ahead scouting the trail in the darkness when he radioed to us about the mountain lion. Come with your sidearms drawn, he said. We figured he was fucking with us. We were talking loudly, walking with our flashlights on—surely a mountain lion would shy away. We continued down the trail until the ground leveled off and it was then that a sharp hiss issued up from the darkness beside us, a sound like hot wind escaping the depths of the earth. Holy fucking shit, we said. We drew our sidearms and shuffled down the path back-to-back, casting light in all directions. I felt a profound and immediate fear—not of the danger posed to us by the animal, but of the idea that it might show itself to us, so many men armed and heedless.

There are days when I feel I am becoming good at what I do. And then I wonder, what does it mean to be good at this? I wonder sometimes how I might explain certain things, the sense in what we do when they run from us, scattering into the brush, leaving behind their water jugs and their backpacks full of food and clothes, how to explain what we do when we discover their lay-up spots stocked with water and stashed rations. Of course, what you do depends on who you’re with, depends on what kind of agent you are, what kind of agent you want to become, but it’s true that we slash their bottles and drain their water into the dry earth, that we dump their backpacks and pile their food and clothes to be crushed and pissed on and stepped over, strewn across the desert and set ablaze. And Christ, it sounds terrible, and maybe it is, but the idea is that when they come out from their hiding places, when they regroup and return to find their stockpiles ransacked and stripped, they’ll realize their situation, that they’re fucked, that it’s hopeless to continue, and they’ll quit right then and there, they’ll save themselves and struggle toward the nearest highway or dirt road to flag down some passing agent or they’ll head for the nearest parched village to knock on someone’s door, someone who will give them food and water and call us to take them in—that’s the idea, the sense in it all. But still, I have nightmares, visions of them staggering through the desert, men from Michoacán, from places I’ve known, men lost and wandering without food or water, dying slowly as they look for some road, some village, some way out. In my dreams I seek them out, searching in vain until finally I discover their bodies lying facedown on the ground before me, dead and stinking on the desert floor, human waypoints in a vast and smoldering expanse.

In 1706 the Italian priest Father Eusebio Kino climbed to the summit of a volcanic peak just south of the international boundary line that would come, nearly 150 years later, to separate the territory of the United States from the contiguous lands of Mexico. From this vantage point, he looked out across a massive dune field and hardened flows of black lava, all the way to the glistening blue arc of the Gulf of California. It was then that Father Kino, the first white man to reach this high and isolated place, recognized what the native people of this desert had long known: that the landmass of Baja California was not the island that conquerors and missionaries had always assumed it to be, but was in fact connected to the rest of the North American continent, a narrow peninsula reaching down into ancient and teeming waters. Across the pale sands and shimmering sea, Father Kino could make out the mouth of the Colorado River and the wooded peaks of Sierra de San Pedro Mártir, the peninsula’s highest range.

Down in the dune field, Father Kino encountered a wandering people. They cleared long strips of dry ground for ceremonies and traced massive figures onto the surface of the earth, human and animal shapes scraped into the desert pavement and lined with carefully placed stones. For untold centuries they had inhabited a landscape of craters, collapsed calderas, and jagged mountains half buried by sand. They met with few other peoples, occasionally trading goods with neighboring tribes and granting passage to those who journeyed across their parched lands on pilgrimages to collect salt at the nearby edges of the sea.

To Father Kino these people were feeble and ragged, barely surviving on a diet of roots and lizards. But they understood that there was life to be had in the desert, a life worth struggling for. To the Europeans the entire region was a malpaís, a bad country, but those who made their lives there knew it as a place inextricable from the terrain that surrounded it, a single unbroken expanse.

After three months we were finally released from the training unit and dispersed into rotating shifts to work under journeymen agents. I was sent to midnights and partnered with Mortenson, a four-year veteran of the patrol. I’ll tell you what, Mortenson said to me on our first shift together, it throws me for a loop every time they assign me to be a journeyman. Seems like just yesterday I was a trainee myself. My first journeyman was salty as shit, Mortenson scoffed. He kept going on about the “old patrol” and the “new patrol,” about how nobody with less than eight years in the field should be a journeyman. But that was before the big hiring push—there’s so many people coming in and out of the station nowadays that even junior agents move up fast. Mortenson smiled. So here I am, your very own journeyman.

Listen, don’t worry about calling me sir or any of that bullshit. He looked over at me as he drove us down the highway. My old man is the hardest-ass cop you’ll ever meet, made me call him sir ever since I can remember. Shit, I’m twenty-three years old and all I’ve ever known is law enforcement. Mortenson stared out into the darkness beyond his headlights. What about you? he asked. I’m twenty-three too, I told him. Well there you go, he said, the last thing I need is a dude my own age calling me sir. But hell, he smirked, I’ll let you wash the ride at the end of the shift.

Early one morning, before dawn, Mortenson brought me to the port of entry. It’s smart to make friends with the customs agents, he told me—they keep their eye on the foot traffic and the vehicles that cross through the port, and we take care of everything in between. If you get these guys to like you, sometimes they’ll throw you some good intel. He introduced me to a supervisor and got permission for us to monitor the video feeds in the camera room. For nearly an hour we watched a grid of dimly lit buildings and roads surrounding the port until the sun slowly began to rise outside, bleeding warmth onto the screens. Mortenson pointed toward a monitor in the far-left corner and we watched as the pixelated figures of two men and a woman cut a hole in the pedestrian fence. We bolted from the room and ran to the site of the breach, rounding the corner just in time to see the men already scrambling back through the hole to Mexico. The woman stood motionless beside the fence, too scared to run.

As Mortenson inspected the breach, the girl wept beside me, telling me it was her birthday, that she was turning twenty-three, pleading for me to let her go and swearing she would never cross again. Mortenson turned and took a long look at the woman and laughed. I booked her last week, he said. She spoke hurriedly to us as we walked back to the port of entry and while Mortenson went inside to gather our things I stood with her in the parking lot. She told me she was from Guadalajara, that she had some problems there, that she had already tried four times to cross. She swore to me that she would stay in Mexico for good this time, that she would finally go back to finish music school. Te lo juro, she said. She looked at me and smiled. Someday I’m going to be a singer, you know. I believe it, I said, smiling back. She told me that she thought I was nice, and before Mortenson returned from the port she snuck her counterfeit green card into my hand. I don’t want to get in trouble at the processing center like last time, she said. I looked toward the port of entry and slipped the card into my pocket. When Mortenson came back we helped her into the patrol vehicle and drove north toward the station, laughing and applauding as she sang “Bidi Bidi Bom Bom” to us from the backseat. She’s going to be a singer, I told Mortenson. The woman beamed. Shit, he said. She already is.

At night, finally allowed to patrol on my own, I sat watching storms roll across the moonlit desert. There were three of them: the first due south in Mexico, the second creeping down from the mountains in the east, and the third hovering just behind me—close enough for me to feel smatterings of rain and gusts of warm wind. In the distance lightning appeared like a line of hot neon, illuminating the desert in a shuddering white light.

At the station I was given the keys to a transport van and told to drive out to the reservation where two quitters had been seen wandering through the streets of a small village. When I arrived it was just after dark and I noticed few signs of life as I drove past the scattered homes, scanning for disheartened crossers. In the center of the village a small adobe church stood in an empty dirt lot, and I saw that the front door had been left ajar. I parked the van and left the headlights shining on the entrance. I walked to the heavy wooden door and leaned with all my weight to push it open, causing a loud and violent scraping to rise up and echo into the dim interior.

Inside the church, the light from my flashlight glinted off tiny strings of tinsel hanging from the ceiling. A large piece of fabric depicting the Virgin of Guadalupe was strung across the front wall, and beneath it I saw two figures lying on a blanket that had been spread out between the pews and the altar. As I approached, a man looked up at me and squinted, holding out his hand to block the light. We were resting a little, he said. It’s just that we are lost, muy desanimados. A woman huddled close to him, hiding her face. The man propped himself up on one elbow and told me that they had crossed four days ago, that their guide had left them behind on the first night when they’d failed to keep pace with the group. They were lost for days, he said, with nothing to drink but the filthy water from cattle tanks. Puede ser muy fea la frontera, I told him. The man shook his head. Pues sí, he replied, pero es aún más feo donde nosotros vivimos.

The man told me that they came from Morelos. My wife and I, we’re just coming to find work, he said. He rubbed his eyes in silence. I have fresh water for you, I told them. At the station there’s juice and crackers. The man looked at me and smiled weakly, then asked for a minute to gather their belongings. He stuffed some things into a backpack, then helped his wife to her feet. Her face was streaked with dried tears, and when she turned toward me I saw that she was pregnant. How many months are you? I asked. The woman looked away and the man answered for her. Seis meses. He smiled. My wife speaks perfect English, he said, shouldering the backpack. He stopped in front of the altar, bowing his head and making the sign of the cross. I waited at the door as he mumbled a prayer. Gracias, he whispered. Gracias.

Outside I looked at their faces in the glare of my headlights. The woman seemed young. Where did you learn English? I asked. Iowa, she told me quietly. I grew up there, she said, I even got my GED. She kept her head down and avoided my gaze as she talked, glancing up only briefly at my uniformed body. Why did you leave? I asked her. She told me that she had returned to Morelos to care for her younger siblings after their mother died. In Morelos I made some money teaching English at the kindergarten, she said, I even tutored the adults in my village, people preparing for the journey north. For a few seconds she seemed proud, and then she shook her head. But the money there, it isn’t enough. She glanced up at her husband. It was my idea to cross, she said. I wanted our child to have a life here, like I did.

The man took a moment to look at me in the light. Listen, he said, do you think you could bring us back to Mexico, como hermano? You could drive us down to the border, he pleaded, you could just leave us there, allí en la línea. Like a brother. I sighed and turned my head, squinting at the darkness beyond the church. I have to bring you in, I told him. It’s my job. The man took a deep breath and nodded and then climbed into the back of the transport van, holding out his arms to help his pregnant wife.

I gestured at a case of water bottles on the floor. You should drink, I told them. I grabbed the metal door of the cage and paused. What are your names? I asked. The man looked at me strangely and glanced at his wife. Then, as if it were nothing, they took turns introducing themselves. I repeated their names and I told them mine. Mucho gusto, I said. They replied with polite smiles. Igualmente. I turned my head and then bolted the cage and shut the door.

In the driver’s seat I turned to look at the couple through the plexiglass. The man held his wife and gently whispered to her, cradling her head. Just before I started the engine I could hear the soft sound of her sobbing. As I drove through the unmarked streets of the village, trying to find my way to the highway, I felt for a moment that I had become lost. Beyond the last house, I saw a white dog in the darkness at the edge of my headlights, staring into the night.

At the station, I sorted through their things with them, discarding perishables and sharp objects. I had them remove their belts and their shoelaces and I tagged their backpacks and handed them a claim ticket. I counted and took note of their money, in pesos and in dollars, and then handed it back to them, telling them to keep it close. Inside the processing center I filled out their voluntary return papers and entered their names into the computer. Before leaving them in their cell I wished them luck on their journey and asked them to be safe, to always think of their child.

Later that night, as I sat in the transport van listening to the calls come out over the radio, I realized I had forgotten their names.

The modern-day boundary between the United States and Mexico was defined largely by the Treaty of Guadalupe Hidalgo in 1848, signed after nearly two years of warfare between neighboring republics. The newly agreed-upon borderline was to begin “on the coast of the Pacific Ocean, distant one marine league due south of the southernmost point of the port of San Diego,” and run east “following the division line between Upper and Lower California” until it reached the Colorado River at the town of Yuma. The treaty dictated that the line would then follow the course of the Gila River from its intersection with the Colorado until it reached the border of New Mexico, at which point the boundary would leave the waters of the Gila in a straight line until it intersected the Rio Grande north of El Paso, where the line would again become fluid “following the deepest channel” of the river until it emptied into the Gulf of Mexico, to be forgotten in the waters of the ocean at a point “three leagues from land, opposite the mouth of the Rio Grande.”

Article V of the treaty mandated that “in order to designate the boundary line with due precision, upon authoritative maps, and to establish upon the ground landmarks which shall show the limits of both Republics . . . the two Governments shall each appoint a commissioner and a surveyor, who . . . shall meet at the port of San Diego, and proceed to run and mark the said boundary in its whole course to the mouth of the Rio Bravo del Norte.” It added that “the boundary line established by this article shall be religiously respected by each of the two Republics.”

Following the ratification of the treaty, both countries appointed commissioners and surveyors to mark the new boundary. The surveying was initially carried out under the questionable supervision of John Russell Bartlett, a well-connected and adventure-hungry bookseller living in New York. After many fits and starts, the commission established the initial point of the boundary on the Pacific coast and marked it with a “substantial monument,” and made a similar determination “at the junction of the Gila and Colorado rivers, where another monument was placed.” Between these two points, the commission marked the boundary with five intermediate monuments.

Several years later, in 1853, the boundary line was modified by the Treaty of La Mesilla, commonly known in the United States as the Gadsden Purchase. Instead of following the natural course of the Gila River across Arizona to the edge of New Mexico, the new agreement stipulated that a rigid and pivoting line would dip south from Yuma and run east to the Rio Grande, adding nearly thirty thousand square miles of territory to the southern edges of Arizona and New Mexico.

In the first article of the new agreement, it was stated that each government would again nominate a commissioner whose duty it would be “to survey and mark out upon the land the dividing line stipulated by this article, where it shall not have already been surveyed and established.” Over the course of three years following the treaty’s ratification, a new survey was undertaken that included many personnel from the original commission. The newly appointed commissioner, William H. Emory, brought great conviction to his work, deeming it “fortunate that two nations, which differ so much in laws, religion, customs, and physical wants, should be separated by lines.” While he regretted that the new boundary should limit the “inevitable expansive force” of the United States, he nevertheless declared with characteristic zeal that “no line traversing the continent could probably be found which is better suited to the purpose.”

In the course of their work along the international boundary, Emory’s surveying parties erected, in addition to the six still-suitable monuments previously established along California’s border with Mexico, the placement of forty-seven monuments along the newly traced line from the Colorado River to the Rio Grande, asserting, for the very first time, the entirety of a boundary that had hitherto existed only on paper and in the furious minds of politicians.

Agents found Martin Ubalde de la Vega and his three companions on the bombing range more than fifty miles north of the border. The four men had been in the desert for six days and had wandered in the July heat for over forty-eight hours without food or water. By the time of rescue, one of the men had already met his death. Of the survivors, one was quickly treated and discharged from the hospital, while another remained in intensive care, recently awoken from a coma, unable to remember his own name. When I arrived at the hospital asking for the third survivor, nurses explained that he was recovering from kidney failure and guided me to his room, where he lay hidden like a dark stone in white sheets.

I had been charged with watching over de la Vega until his condition was stable, at which point I would transport him to the station to be processed for deportation. I settled in a chair next to him, and after several minutes of silence, I asked him to tell me about himself. He answered timidly, as if unsure of what to say or even how to speak. He apologized for his Spanish, explaining that he knew only what they had taught him in school. He came from the jungles of Guerrero, he told me, and in his village they spoke Mixtec and farmed the green earth. He was the father of seven children, he said, five girls and two boys. His eldest daughter lived in California and he had crossed the border with plans to go there, to live with her and find work.

We spent the following hours watching telenovelas and occasionally he would turn to ask me about the women in America, wondering if they were like the ones on TV. He began to tell me about his youngest daughter, still in Mexico. She’s just turned eighteen, he said. You could marry her.

Later that afternoon, de la Vega was cleared for release. The nurse brought in his belongings—a pair of blue jeans and sneakers with holes worn through the soles. I asked what had happened to his shirt. I don’t know, he answered. I looked at the nurse and she shrugged, telling me he had come in that way. We’ve got no clothes here, she added, only hospital gowns. As we exited through the hospital lobby, I watched the way eyes fell across his shirtless body. I imagined him alone and half naked in the days to come as he was ferried through alien territory, booked and transferred between government processing centers and finally bused to the border to reenter his country.

In the parking lot I placed him in the passenger seat of my patrol vehicle and popped the trunk. At the back of the cruiser I unbuckled my gun belt, unbuttoned my uniform shirt, and removed my white V-neck. I reassembled my uniform and returned to the passenger door to offer him my undershirt.

Before leaving town, I asked him if he was hungry. You should eat something now, I told him, at the station there’s only juice and crackers. I asked what he was hungry for. What do Americans eat? he asked. I laughed. Here we eat mostly Mexican food. He looked at me unbelievingly. But we also eat hamburgers, I said. We pulled into a McDonald’s and at the drive-through window de la Vega turned to me and told me he didn’t have any money. Yo te invito, I said.

As we drove south along the open highway, I tuned in to a Mexican radio station and we listened to the sounds of norteño as he ate his meal. After finishing he sat silently next to me, watching the passing desert. Then, as if whispering to me or to someone else, he began to speak of the rains in Guerrero, of the wet and green jungle, and I wondered if he could ever have been made to imagine a place like this—a place where one of his companions would meet his death and another would be made to forget his own name, a landscape where the earth still seethed with volcanic heat.

As I cut for sign along the border road, I watched a Sonoran coachwhip snake try to find its way into Mexico through the pedestrian fence. The animal slithered along the length of the mesh looking for a way south, hitting its head against the rusted metal again and again until finally I guided it over to the wide opening of a wash grate. After the snake had made its way across the adjacent road, I stood for a while looking through the mesh, staring at the undulating tracks left in the dirt.

A woman on the south side of the pedestrian fence flagged me down as I passed her on the border road. I stopped my vehicle and went over to her. With panic in her voice she asked me if I knew about her son—he had crossed days ago, she said, or maybe it was a week ago, she wasn’t sure. She hadn’t heard anything from him, no one had, and she didn’t know if he had been caught or if he was lost somewhere in the desert or if he was even still alive. Estamos desesperados, she told me, her voice quivering, with one hand clawing at her chest and the other trembling against the fence. I don’t remember what I told her, if I took down the man’s name or if I gave her the phone number to some faraway office or hotline, but I remember thinking later about de la Vega, about his dead and delirious companions, about all the questions I should have asked the woman. I arrived home that evening and threw my gun belt and uniform across the couch. Standing alone in my empty living room, I called my mother. I’m safe, I told her, I’m home.

Three decades after signing the Treaty of La Mesilla, successive conventions of Mexican and United States diplomats convened in Washington, D.C., in 1882, 1884, and again in 1889, to discuss the state of the boundary between the two nations. In the years since the last boundary commission had concluded its work in 1856, settlers had been moving to the southwest in growing numbers to work on landholdings and newly discovered mines adjacent to the international border. In many places, the exact location of the boundary had become a matter of contentious debate, presenting great difficulty to government authorities on both sides of the line. In some cases, it was even charged that quarreling parties had destroyed or removed the boundary markers that had been erected at great cost to both countries in the previous decades.

During the course of these binational meetings, representatives of both countries agreed on the pressing need to determine “(a) the condition of the present boundary monuments; (b) the number of destroyed or displaced monuments; (c) the places, settled or capable of eventual settlement, where it may be advisable to set the monuments closer together along the line than at present; (d) the character of the new monuments required, whether of stone or iron; and their number, approximately, in each case.” The conventions thus called for the establishment of a new international boundary commission, which was to possess the power and authority to reposition incorrectly placed or missing monuments, “to erect new monuments on the site of former monuments when these shall have been destroyed,” and “to set new monuments at such points as may be necessary and be chosen by joint accord.”

In keeping with the trend toward consolidating a well-demarcated and enforceable line, the convention agreements stipulated “that the distance between two consecutive monuments shall never exceed 8,000 meters, and that this limit may be reduced on those parts of the line which are inhabited or capable of habitation.” In the course of their ensuing work, the commission found that most of the original markers were “but rude piles of stone . . . while the intervals between them were found to be in some cases as great as 20 or 30 miles . . . and in one instance 101 miles.” Some monuments had disappeared altogether, spirited away by wind and water or swallowed by the landscape, as if they had never existed at all.

The fulfillment of the commission’s duties ultimately led to the repair and replacement of 43 of the original boundary markers and the erection of 215 new iron monuments. The report filed by the commission boasted that the 675 miles of borderline that ran from the Pacific coast to the Rio Grande were now better established and more clearly marked than ever before, with the average distance separating the monuments a mere 2.6 miles. It thus became likely, for the first time in history, that a person crossing north or south at any point along the line would see evidence of a boundary laid out upon the earth, tiny obelisks reaching up toward the vast arc of the sky.

Morales and I arrested two men walking aimlessly through the desert night, far from any known trail. The men did not run but fell to their knees, their hands trembling above their heads in the pale glow from our flashlights. They followed our commands, nodding timidly. As we walked them single file to the patrol vehicle, I observed their gait—heavy and sapped of purpose.

Outside the processing center, Morales and I talked with the men while we searched their belongings. They were our age, mid-twenties, and both hailed from the same mountain village in Oaxaca. One of them wore a baseball hat with the image of a marijuana leaf embroidered on the front. You think it’s cool to wear a hat with marijuana on it? Morales asked him. The man seemed confused. I didn’t know it was a marijuana hat, he said. It’s the only kind they were selling. His companion, small and potbellied, listened in, concerned. Is that what marijuana looks like? he asked.

Morales and I rummaged through the men’s backpacks, setting aside liquids, perishable foods, and anything that might be used as a weapon. In the bag that belonged to the man with the hat, Morales uncovered a pouch of thickly cut carne seca. The man smiled. I prepared it myself, he said, standing a little straighter. Morales looked longingly at the jerky. Have some, the man offered—no se echa a perder. No thanks, Morales said.

At the bottom of the potbellied man’s backpack I discovered a bag of grasshoppers and another filled with small dried fish. The man chuckled. Comida típica de Oaxaca, he said. Try the chapulines, he suggested, pointing at the grasshoppers. I shook some into my palm and glanced at Morales before tossing them into my mouth. The Oaxacans laughed. Not bad, I said. Tastes like salt and lime. The men looked at me eagerly. See if you like the charales, they said, gesturing toward the dried fish. I took one into my mouth, grimacing from the heavy salt. I dared Morales to do the same. Fuck it, Morales said, I’m eating that jerky. For a short time we stood together with the men, laughing and eating, listening to their stories of home.

As Morales prepared to escort them into the processing center, I gathered up the items to be discarded. I was about to toss a small water bottle when the potbellied man whispered that I shouldn’t throw it away, that it held mezcal made on his family’s ranch. His father had harvested the maguey from the mountains around their village, he told me, and it had been aging for six months. It’s at its best right now, he said, take it with you. No se echa a perder.

Near the end of my shift, Mortenson called me into the processing room and asked me to translate for two girls who had just been brought in, nine- and ten-year-old sisters who were picked up with two women at the checkpoint. He told me to ask them basic questions: Where is your mother? In California. Who are the women who brought you here? Friends. Where are you from? Sinaloa. The girls peppered me with nervous questions in return: When could they go home? Where were the women who drove them? Could they call their mother? I tried to explain things to them, but they were too young, too bewildered, too distraught at being surrounded by men in uniform. One of the agents brought the girls a bag of Skittles, but even then they couldn’t smile, they couldn’t say thank you, they just stood there, looking at the candy with horror.

Once agents placed the girls in a holding cell, I told Mortenson I had to leave. My shift’s over, I said. He told me they still needed to interview the women who were picked up with the girls and asked me to stay and translate. I can’t help anymore, I told him, I’ve got to go home. As I drove away from the station I tried not to think of the girls, and my hands began to shake at the wheel. I wanted to call my mother, but it was too late.

Several hours after sundown, Morales and I met at a remote trailhead to respond to a sensor hit. We hiked slowly by starlight across stony foothills to the place where a small trail dropped down from a low mountain pass. Morales took his flashlight and crouched to the ground with his hand over the face cap, shining a muted light over a small patch of dirt on the trail. This sign is days old, he whispered. He looked up at the black outline of the mountains. I’ll bet whoever set off that sensor is still laid up at the top of the pass.

We decided to wait for the group to come down the trail. We concealed ourselves behind a gnarled mesquite tree, Morales sitting cross-legged and me sprawled out on the desert floor, twisting my body until I found a patch of ground free from rocks. Morales smoothed a swath of earth with his hands and began to trace swirling lines as I gazed upward, transfixed by the Milky Way trailing across the sky like a cloud of glimmering dust. For over an hour the whirring of a nearby cricket and the soft pattering of kangaroo rats were the only sounds we heard. Periodically, I broke the silence to call attention to a shooting star, whispering to Morales to ask if he had seen it. Si vato, lo vi.

After another hour of silence, I reached out to touch Morales’s knee. Qué? he replied. How much longer do you want to stay here? I asked. Shit, he said, I don’t know. We were silent again. I’ll bet you there’s scouts in these hills, I finally said. They must have watched us hike in. Morales threw a stick at the patch of dirt in front of him. Maybe the sensor hit was bad, he said. We could hike up the pass. If they’re still laid up we can bust the group, and if nobody’s there we’ll check the sensor for foot sign. I shook my head. If there are scouts, the group is long gone. If there’s no scouts and the group is still up there, they’ll hear us coming before we get anywhere close. I’ve been up that trail with Mortenson, I told him. The last quarter mile is steep as hell and covered in loose shale. And if the sensor hit was bad in the first place, I said, well, then it’s an even bigger waste of time.

We walked back across the desert toward our vehicles. I paused to look up once more at the moonless night sky, and Morales continued past me. After his footsteps had grown distant, I noticed a tiny point of light drifting slowly across the black dome of the sky. Without moving my head, I called out to Morales. Come back here, I shouted into the night. I could hear him grumbling as he made his way back to where I had stopped. Qué chingados quieres? Look, I said, pointing up at the sky. I don’t see anything, he complained. It’s a satellite, I said, traveling away from the North Star. Shit, Morales finally said, I see it. Cabrón, I’ve never seen one of those before. Me neither, I said. We stood enveloped by silence as we stared at the sky, surrounded by figures hidden away in the hills and the mountains, figures gazing up at the very same stars, toward barely discernible satellites barreling through the atmosphere, small bodies tenuously tethered to their orbits at the outermost limits of the earth.

When the call came out on the radio, I braced myself for the smell. That’s the worst part, the senior agents would always say, the smell. During my first week at the station, one of them suggested I carry a small tin of Vicks VapoRub with me wherever I went. If you come upon a dead body, he said, rub that shit under your nose, or else the smell will stay with you for days.

I arrived at the scene in the still-hot hours of the early evening. Hart had already been with the body for thirty minutes. It’s fresh, he told me, maybe two hours old. It doesn’t smell yet. Hart had been flagged down by two teenagers as he was driving across the reservation. They put rocks in the road, he said, gesturing awkwardly toward the boys. He stood with his hands in his pockets and then asked me if I would talk to them. They keep asking me questions, he said. I can’t understand them.

One of the boys was sitting on a rock, looking disoriented. I went over to him and asked how he knew the dead man. Es mi tío, he told me. He stared at his hands as he spoke. How old are you? I asked. Dieciséis. I looked at his friend, standing a few feet away with his hands in his pockets. And you? He looked up from the ground. Diecinueve, he said.

The dead man and the two boys all hailed from the same village in Veracruz and had set out together on the journey north. The nineteen-year-old did most of the talking, telling me that a few hours before the man died, he had taken two Sedalmerck pills, caffeine uppers that border crossers often take for energy, and had washed them down with homemade sugarcane liquor they had brought from Veracruz. A few hours later, he said, the man was staggering around like a drunk, and then he collapsed.

I walked over to the body. Hart had placed a shirt over the dead man’s face. I lifted it and looked at him. His eyes were closed and he had long dark hair that already looked like that of a dead man. White foam had bubbled up and collected between his parted lips and his face was covered with small red ants traveling in neat lines toward the moisture. His shirt was pulled up at the sides of his abdomen and I could see where his skin was turning purple with dependent lividity as his blood settled to the ground. With the toe of my boot I gently moved his arm, already stiff with rigor mortis.

The nineteen-year-old told me that the three of them had become separated from their group. Their guide had told them to spread out, to hide in the bushes by the road to wait for the load vehicle. They must have gone too far, he said, because sometime later they heard a car stop and then drive off and after that they couldn’t find anyone. Alone at the edge of the road, they walked for several miles in the August heat until the dead man finally lay down to die. The boys waited beside the road to flag down one of the infrequently passing cars, but no one stopped for them. That’s why they put the rocks out, they said, to make the cars stop.

The boys asked me what would happen to the dead man, if they could come with the body to the hospital. I told them that they could not, that they had to stay with us, that they would be processed for deportation and that the body would be turned over to the tribal police. They asked if the body would come back to Mexico with them, if they could bring it back to their village. I told them that they could not, that the body would be taken to the county medical examiner, who would try to determine the cause of death. I told the boys they would be taken to the sector headquarters, where they would meet with the Mexican consul, that it was the consul who would make arrangements for the repatriation of the body to Mexico. As I spoke, the man’s nephew stared at the ground. Maybe the consul can provide you with some documentation, I suggested, something to take home to your family.

The boys didn’t want to leave the body, and even as I explained the procedures to them I began to doubt, given what I knew from my short time on the border, whether they would actually see the consul, whether the consulate would actually arrange for the body to go back to Mexico, whether the boys would even receive a piece of paper to help explain to the dead man’s family what had befallen him on the journey north. As I spoke to them, Hart came over and instructed the boys to take off their belts and shoelaces and any watches, necklaces, or other jewelry they might have, and to take from their pockets any lighters, pens, knives, or other sharp objects. I looked at Hart. Transport is coming, he said.

Another agent, junior even to Hart and me, arrived to transport the boys back to the station. He brought a camera to photograph the body and as he took his pictures I noticed the dead man’s nephew watching in a sort of trance. I explained to the boy that the pictures were required by the police, that they were needed for the reports we had to file at the station, and he nodded his head as if he had heard and understood nothing, like he just knew it was what he was supposed to do.

Before the boys were loaded into the transport unit, I went to them and told them I was sorry for their loss. It’s a hard thing, I said. I told them that if they ever decided to cross again, they must not cross in the summer. It’s too hot, I said—to cross in the heat is to risk one’s life. I told them never to take the pills the coyotes gave them, because they suck moisture from the body. I told them that many people died there, that in the summer people died every day, year after year, and many more were found hovering at the edge of death. The boys thanked me, I think, and were placed into the transport unit and driven away.

The sun had already begun to set as I left the body, and it cast a warm light on the storm clouds gathering in the south. As I drove toward the storm, the desert and the sky above it grew dark with the setting of the sun and the coming rain. When the first drops hit my windshield I could hear the dispatch operator radio to Hart, who had stayed behind with the body, that the tribal police didn’t have any officers available and that he’d have to wait with the dead man a while longer.

Later that night, at the end of our shift, I saw Hart back at the station and asked what had happened with the body. He told me that finally the storm had come and dispatch had told him to just leave the body there because the tribal police wouldn’t have an officer to take charge of it until the next day. It’s all right, he told me, they have the coordinates. I asked him if it had been strange waiting there in the dark, watching over the body of a dead man. Not really, he said. At least he didn’t smell yet.

We stood for a few more minutes talking about the storm and about the human body that lay there in the desert, in the dark and in the rain, and we talked of the animals that might come in the night and of the humidity and the deadly heat that would come with the morning. We talked, and then we went home.

I dream in the night that I am grinding my teeth out, spitting the crumbled pieces into my palms and holding them in my cupped hands, searching for someone to show them to, someone who can see what is happening.

The various men called upon to survey the nascent border between the United States and Mexico in the years following the ratification of the Treaty of Guadalupe Hidalgo could not help but comment on the strangeness of their task and the extreme and unfamiliar nature of the landscape. In places, commission reports remarked upon the “arbitrarily chosen” nature of the boundary line and the “impracticable” nature of their work. Survey members noted that “indeed much of this country, that by those residing at a distance is imagined to be a perfect paradise, is a sterile waste, utterly worthless for any purpose other than to constitute a barrier or natural line of demarcation between two neighboring nations.” After the Gadsden Purchase, Lieutenant Nathaniel Michler observed to Commissioner William H. Emory that “imagination cannot picture a more dreary, sterile country . . . The burnt lime-like appearance of the soil is ever before you; the very stones look like the scoriae of a furnace; there is no grass, and but a sickly vegetation, more unpleasant to the sight than the barren earth itself.”

More than thirty years after the original survey, subsequent surveyors found that the lands adjacent to the border remained “thinly settled” and noted “the prevalence of thorns in nearly all vegetation; the general absence of fragrance in flowers; the resinous character of the odor of the most common trees and shrubs.” Giant cacti were described as “strange, ungainly, helpless-looking objects” with “clumsy arms.” In places, the borderlands were “beautiful beyond description,” with mountains “rising out of the plains like islands from the sea,” but elsewhere the landscape was “a hopeless desert,” a place of “loneliness and desolation.”

The field party that departed from El Paso in February of 1892 to begin the work of re-surveying and re-marking the boundary was a massive force numbering about sixty, which included several commissioners, engineers, and astronomers, as well as a secretary, a field clerk, a wagon master, a blacksmith, a quartermaster, a carpenter, a medical officer, a recorder, a photographer, a topographer, a draftsman, a levelman, and multiple transitmen, rodmen, targetmen, teamsters, packers, cooks, and other helpers. To carry their supplies, the group traveled with eighty-three mules and fourteen saddle ponies. The expedition was further provided by the U.S. War Department with a military escort of twenty enlisted cavalrymen and a detachment of thirty infantrymen “as a protection against Indians and other marauders.”

In the opening days of the expedition “men and animals were new and unseasoned to hardship, but in a few days the majority became accustomed to field life, and the work soon progressed rapidly and satisfactorily.” To reaffirm the course of the line, latitude was determined by astronomers and their assistants using the “Talcott method” or through an “exchange of signals by telegraph” over the course of ten nights in which the same stars were observed from distant stations. The men also used chronometers, bull’s-eye lanterns, steel tape, a Bessel spheroid, a zenith telescope mounted on brick pier, a sextant mounted on a wooden pier, and a Fauth repeating theodolite “furnished, on the horizontal motions, with axis clamps and tangent screws working against spiral springs.”

As the surveying party moved across the boundary, contingents of men were continually convened and reconfigured and sent by rail or caravan to initiate duties along distinct sections of the line. These contingents often worked out of new settlements along the border, and the commission’s report noted “the grasping and overreaching action of the United States settlers” and “the kindness and courtesy of the Mexican officials.” In some areas, the newly annexed terrain was so remote and unknown as to necessitate the dispatching of reconnaissance parties to secure reliable information “concerning water, roads, and the general topographical features of the country.” The surveyors described the landscape as bare and ragged, desolate and rough, punctuated by rocky hills and steep, narrow-ridged mountains of stratified limestone and porphyry, red basalt and igneous rock thrust upward alongside empty craters and extinct volcanos surrounded by broken lava.

As they traversed the farthest-flung corners of the desert, the surveying parties passed the gravesites of travelers who had perished before them. “In a single day’s ride,” the commissioners reported, “sixty-five of these graves were counted by the roadside, one containing an entire family, whose horses gave out and who, unable to cross the scorching desert on foot, all perished together of thirst. Their bodies were found by some travelers during the following rainy season, and were all buried in one grave, which is covered with a cross of stones.” As they cautiously made their way along the infamous Camino del Diablo, their reports noted that “during the few years that this road was much traveled,” in the rush to California of the 1850s and 1860s, “over 400 persons were said to have perished of thirst . . . a record probably without a parallel in North America.”

The surveyors made it clear that “supplying the working parties with water on the deserts was the problem of the survey, in comparison with which all other obstacles sank into insignificance.” The commission’s final report revealed that the terrestrial portion of the line, “although having a total length of about 700 miles, crosses but five permanent running streams between the Rio Grande and the Pacific.” The report took special care in describing the point where the boundary line gave itself over to the Rio Grande, “a variable stream with turbid waters.” The river carried “an immense amount of sediment,” it noted, “and as a consequence it is bordered by alluvial bottoms, through which by erosion, it is continually changing its bed.” It was as if the surveyors wished to acknowledge how the border, no matter how painstakingly fixed upon the land, could go on to endlessly change its course with the whims of a river.

Walking to my truck at the end of my shift, I saw Mortenson standing outside the armory with a group of agents. I went up to greet him and then listened as an agent named Beech told the other men about his time as a prison guard. There was this one guy, Beech said, we couldn’t keep the bastard from cutting himself. Swear to god, all he thought about all day was how to slash through his own skin. There was hardly a thing he wouldn’t find a way to cut himself with. I’m talking pencils, pieces of plastic, chunks of cardboard, you name it. Shit, even magazines—I came into his cell one day and his forearms were covered in paper cuts and a thousand little blood droplets, and this guy just stared up at me like a fucking deer in the headlights. That’s fucked up, muttered Mortenson. Hell, said Beech, that’s nothing. This same motherfucker, one day I get called into his cell and he’s just sitting there with his crotch all covered in blood. Dude had sliced his cock up with a filed-down plastic spoon, I shit you not. The other agents yelled out and one of them threw an empty can of Monster at Beech’s feet. For Christ’s sake, one cried, holding his stomach. Beech laughed. Shit, he said, how do you think I felt? You should have heard me call that one in to the nurse.

An older agent named Navarro shook his head and grabbed his gun belt, hoisting it a little higher under his sagging belly. Some people are just like that, he said, les vale madre. A few of the other agents nodded. I was in Iraq with this crazy white kid, Navarro told the group, he had one of those cock piercings. The agents winced. Other guys in the unit were always giving him shit because he was into heavy metal and freaky as hell. We started calling him Marilyn Manson. Mortenson chuckled and Navarro glanced at him. It gets worse, vato. This kid was always looking at these fucked-up magazines, pornos with tattoos and piercings and shit, and one day he shows me a picture of a cock head split right down the middle, like a forked snake’s tongue. I shit you not, the kid looked at me with a straight face and told me it was next on his to-do list. The agents burst out into a chorus of groans and the same agent who had thrown the can of Monster called out to Navarro over the jeers. Did he show it to you or what? The other agents laughed. Navarro pulled his belt up again and shook his head. Kid never had a chance, Navarro replied. A week later he got blown up, vato, just like that. I saw it with my own eyes.

The other agents became quiet and several of them looked down at the ground with awkward shame. But Beech remained with his head held up, glancing at Navarro to share a brief nod, as if in acknowledgment.

Morales was the first to hear him, screaming in the distance from one of the dirt spider roads. He hiked for a mile or two and found a teenage kid lying on the ground, hysterical. For more than twenty-four hours he had been lost in a vast mesquite thicket twenty miles from the border. The coyote who had left him there told him he was holding back the group. He handed the kid half a liter of water, pointed to some hills in the distance, and directed him to walk toward them until he found a road.

When I arrived the kid was on the ground next to Morales, lurching in the shade and crying like a child. He was fat—his pants hung from his ass and his fly was half open, his zipper broken, his shirt hanging loosely from his shoulders, inside out and torn and soaked in sweat. Morales looked at me and smiled and then turned to the kid. Your water’s here, gordo. I kneeled next to him and handed him a gallon jug. He took a sip and began to pant and groan. Drink more, I said, but drink slowly. I can’t, he moaned, I’m going to die. No you’re not, I told him, you’re still sweating.

After the kid drank some water, we helped him up and tried walking him through the thicket toward the road. He lagged and staggered, crying out behind us. Ay oficial, he would moan, no puedo. As we crouched and barged through tangled branches, I slowly became overwhelmed by his panic until finally we broke out of the thicket and spotted the dirt road. You see the trucks, gordo? Can you make it that far? Maybe we should just leave you here, no puedes, verdad?

On the ride back to the station, the kid regained some composure. He told me he was eighteen, that he had planned to go to Oregon to sell heroin, un puño a la vez. I hear you can make a lot of money that way, he said. For several minutes he was silent. You know, he finally told me, I really thought I was going to die in that thicket. I prayed to God that I would get out, I prayed to the Virgin and to all the saints, to every saint I could think of. It’s strange, he said, I’ve never done that before. I’ve never believed in God.

I finally went to the hospital to see Morales. He’d been in a motorcycle accident. He hadn’t been wearing a helmet, and for a while we had been hearing about his head trauma, that he might not make it. I’d been too afraid to see him during the week he’d spent in a coma, and too afraid, still, to see him during the first days after he came out of it, when he would wake up cursing and pulling his tubes out, when he still didn’t recognize anyone.

Walking into his hospital room, I was surprised by how thin he was, how frail he seemed. He had bruises under his deep-set eyes, a feeding tube in his nose, an IV line in his arm, and a huge gash across the left side of his skull where half his hair had been shaved off. Ey vato, he whispered to me. I smiled at him. I like your haircut, I said. He seemed far away, his eyes scanning the room as if searching for some landmark, something to suggest the nature of the place he had come to.

Morales’s childhood friend from Douglas was there and told me Morales couldn’t see out of his left eye, but the doctors thought the sight would come back eventually. Morales’s mother and father were there too, speaking softly to each other in Spanish. A little while after I arrived, Cole and Hart came, still in uniform after finishing their shift. They stood over Morales, and Cole reassured him that soon he’d be back in the field raising hell just like before. I could see a wet glaze in Cole’s eyes as he spoke. I excused myself from the room, saying I’d come right back.

Outside I stood in the parking lot, trying to gather my strength. I thought about the tears in Cole’s eyes, about Morales’s far-off gaze, about his parents huddled in the corner, becoming smaller and smaller as uniformed agents filled the room to hover at their son’s bedside. My face became hot and I could feel moisture collecting in my eyes. The glare of the sun grew brighter. The outlines of the surrounding cars and trees grew sharp and began to blur. I closed my eyes and took a deep breath. I would not go back, I decided, I would not let the water gather into tears.

Late in the afternoon I took the border road out to the lava flow, driving for more than an hour across rocky hills and long valleys. The earth became darker as I neared the flow, devoid of brush and cactus. To the south a pale band of sand dunes underlined the base of a nameless cordillera, shifting at the horizon in shades of purple and dark clay. As I drove slowly over the lava flow, I looked out across black rocks glistening as if wet in the afternoon sun, rocks pockmarked from when the earth had melted and simmered between erupting volcanoes, a molten crust cracking and shifting as it cooled.

Driving along a small dirt road through the reservation, I was waved down by a man in a passing car. We each pulled over on the side of the road and exited our vehicles to talk. The man was tall with long hair and he stared into the distance as he spoke. He introduced himself as Adam, telling me he lived in a nearby village with his family, a place agents referred to as the vampire village. He told me that strange vehicles had been passing through the village, vehicles he didn’t recognize as belonging to any of the residents. It’s a small place, he said, only us Indians have any reason to visit. People don’t pass through unless they’re from there, unless they have family there or something.

Adam’s wife stepped out of the car and joined us at the side of the road. She stood close to her husband and kept her hands in her pockets except to sweep back the hair from her face. She began to speak to me slowly, as if measuring her words. This morning, she said, just after Adam left for work, a group of men came to our door. I was alone—it was just me and my son. She gestured at their car and her hand trembled in the air. Their son sat alone in the backseat, playing with a misshapen toy figurine. The boy wore glasses like his father and as I glanced at him I noticed how his body would occasionally seize as if struggling to contain some inner terror. Suddenly the boy began to thrash his head and then he looked out the window at us, his eyes magnified by his thick lenses, his mouth open wide as if shrieking in pain.

The men at the door asked me for water, Adam’s wife continued, but they weren’t wearing backpacks, they didn’t look like normal crossers. How do you mean? I asked. We live twenty miles from the border, she explained, lost migrants pass through all the time. But these men were different, they didn’t seem lost. They weren’t tired, they weren’t afraid, you know? They were wearing camouflage pants and they didn’t have backpacks. They always have backpacks.

You know, whenever people come to our door, she continued, we give them water and we call the Border Patrol right away and they always just sit there, waiting to get picked up. They just want out of the desert. But these men got upset when I said I was calling Border Patrol. You better not, they said. Then they demanded food and more water. I didn’t feel like I had a choice, so I gave them what they wanted and they took it with them back into the desert.

We’ve had break-ins before, Adam said, while we were away. They rummage through the house, you know, like they’re looking for guns or something. They leave things a mess, but all they ever take is food. And they leave the water running, they always leave the water running.

Adam’s wife looked down at her feet and continued her story. Later that morning, she said, I heard these noises from out in the desert, like big branches were being snapped in half or something. It was so loud it woke my boy. A couple hours after that I watched through the window as this minivan drove into town past our house and parked next to the church. It looked like it had broke down—there was smoke coming up from under the hood and everything. Two men got out, a Mexican and an Indian, and they started going through the village from door to door. That’s when I called Adam at work.

I told her to lock up the house, Adam said, to put the blinds down and wait for me to get home. We’ve never seen that van before, you know. It’s still parked there, right in front of the church. I looked at Adam and his wife. I’ll go take a look at the van and run its records, I finally said. If you give me your number, I’ll let you know if I find anything.

Soon after Adam and his wife drove off, I stopped a slow-moving vehicle with three occupants driving north from the village. The driver was Mexican and had a shaved head and a cold look about him. He was covered in tattoos, with two teardrops inked at the corner of his left eye. Next to him, a drunk and toothless man swayed in the passenger seat. I asked the man his name and he told me I could call him Michael Jackson. Everyone in the car burst out laughing. Just kidding, he said, I’m an Indian. Everyone laughed again, even harder.

I asked the woman in the backseat for her ID, and when she reached for her purse I stopped her. There better not be any weapons in there, I said. She looked at me and began to laugh and everyone else laughed too, louder than before, in a way that made me sick. I called in their records and was informed by dispatch that the drunk man had a warrant from the county sheriff for drug smuggling. I told dispatch that the man was a tribal member, and asked for assistance from the tribal police.

Back at the car I asked the drunk man to step outside and I escorted him to my patrol vehicle. There’s a warrant for your arrest, I told him. Oh, he said, that’s okay. I’m going to handcuff you and place you in the back of my vehicle until we get it sorted out, do you understand? That’s okay, he said, swaying. I shut the man in the backseat and watched him double over and begin to weep.

I walked back to the car and asked the driver for consent to search the vehicle. The man glared at me. Listen asshole, I said, you can stare at me all you want, but your buddy’s smuggling warrant gives me probable cause to search this vehicle with or without your consent. The man shrugged his shoulders. The car’s hers, he said, nodding to the woman in the backseat, I don’t give a shit what you do. I ordered the man to step outside for a pat-down and the woman began laughing to herself. The driver stared glassy-eyed into the distance as he spread his legs and leaned with his arms splayed against the vehicle. As I pulled a knife from his pocket, I looked up to see his gaze fixed on the distant dust cloud of an approaching police truck.

The tribal police officer, barely nineteen years old, stood at the edge of the road with the tattooed man and the laughing woman as I searched their vehicle. After the search yielded no results, I walked over to the man and threw him the keys to the car. Be on your way, I told him, Michael Jackson stays with us. The woman shuffled back to the car and the man smirked at me, a glint in his eye. As the car slowly made its way up the road, I asked the tribal officer what would happen to the drunk man. Well sir, he told me, I just got word from my supervisor that his warrant is non-extraditable outside of county jurisdiction. He’s lucky you stopped him on the res. I shook my head. The officer shrugged. But since he’s drunk as hell I’ll take him back to the station until he sobers up or someone comes to get him, whichever comes first.

It was dark when I finally drove down the dirt road that led to the vampire village. The place seemed abandoned and I saw no lights except for a lamp hanging in front of the old adobe church. The minivan that Adam’s wife had mentioned was still there, covered in dust and surrounded by foot sign. I called dispatch to run the plates and the VIN, but the records came back clean. Through the heavily tinted windows I could see that the backseats had been removed. The inside was covered in dirt and strewn with burlap twine and empty water jugs. There were two spare tires and an extra car battery and patch kits and cans of Fix-A-Flat scattered across the floor. I followed the vehicle’s tire sign through the empty village to the two-track that passed by Adam’s house. In the desert beyond the house I saw several places where brush had been run over and tree branches had been broken to make way for the vehicle’s passage. At the end of the two-track, the tire sign turned into the open desert and the ground became rocky and hard to cut. I inspected the ground for toe digs and kicked-over rocks with my flashlight and scanned the tangled scrub at the edge of the wash for blackened water jugs and spray-painted bundles. I stopped walking and turned off my light to listen. I knew that the men in camouflage were out in the desert. I knew that they had emptied the broken-down van and brushed their load up in some nearby wash or thicket, that they were waiting for the right time to move it again, to load it into some other disposable stripped-down vehicle. And I knew, finally, that I would not find them.

Before driving back to the station, I called Adam at the number he had given me earlier in the day. He was home and I could hear his son crying in the background. I told him that the van’s records had come back clean, that I had followed the two-track south of his home and hadn’t found anything. I told him that he should call the station if the men came back to the house or if he heard any more strange sounds coming from the desert. He was silent for a moment and then he thanked me. I could hear the muffled voice of his wife and I knew she was still afraid, and I began to wonder if I was doing them some grave disservice, if I should tell them that I had seen the men from the van, that they were still out there and that the men in camouflage were still out there too, and that they would all come back, that they would forever remember the location of Adam’s home, that they would not forget his wife and her suspicion. I wanted to tell him to take his young family and move somewhere new, somewhere far from the border, somewhere where his home would not be at the remote crossroads of drug routes and smuggling corridors. I stared out the windshield as I thought of what to say. Finally, I asked Adam why everyone called his village the vampire village. He thought for several seconds and then said he didn’t know. He chuckled at first and then he began to laugh and I laughed too because I wasn’t sure what else to do. I laughed and kept the phone to my ear, waiting for him to say something more.

On my way home from working the swing shift, I saw a man lurking in the darkness at the corner of my street. It was early in the morning, maybe two or two-thirty, and the man was alone, standing under the streetlight as if he was waiting for someone. My headlights passed over him when I turned onto my street, and I could see that he had a shaved head and tattoos. He didn’t look at me, but he watched my truck as I passed, and I was seized by a sickening feeling that I was the one he was waiting for.

I continued past my house and kept going for several blocks before turning down a side street. I kept driving, slowly making my way through the neighborhood, not knowing where to go. After a while I felt foolish and turned around to make my way back home. I drove by the corner where I had seen the man and no one was there, just the empty sidewalk, yellow and broken beneath the streetlight. I made a full circle around the block and still I saw no one, so I pulled into the dirt alleyway behind my house and switched off the headlights as I approached my driveway.

I exited my vehicle quickly, leaving my things inside. I went into my house without turning on the lights and made my way through the rooms, still wearing my uniform and my gun belt. I called the police department on my cell phone, pacing back and forth in my kitchen as I told the dispatcher about the man I had seen standing outside my home. I’m an agent, I said. Oh, the woman replied, we’ll send someone right away. I hung up the phone and stood alone in the darkness of my living room, hunched next to a window, peering through the blinds at an empty street.

I drove alone to the firing range at the edge of town. A cold wind was whipping across the grounds, so I piled rocks at the foot of my target stand to keep it from blowing over. Against the cardboard backing, I stapled a large sheet of paper printed with the gray silhouette of a man, concentric squares descending into his chest. I stood at various distances from the target: three yards, seven yards, fifteen yards, twenty-five yards. I practiced unholstering and firing my service weapon with both hands, with one hand, with my body bladed to the left and to the right, kneeling and from the hip, standing on either side of a barricade.

After completing the course of fire, I shot at a smaller target with my own .22 caliber pistol. As I paused to reload, a yellow bird landed atop the target stand. I waited for it to fly off, but the bird continued hopping across the top. I started to walk downrange to scare it off, and then I stopped. I looked around. The range was empty. It occurred to me then that perhaps I should shoot the bird, that I should prove to myself that I could take a life, even one this small.

I dropped the little bird with one shot. I walked over and picked up its body and in my hands the dead animal seemed weightless. I rubbed its yellow feathers with my fingertip. I began to feel sick and I wondered, for one brief moment, if I was going insane. At the edge of the firing range I dug a small hole beneath a creosote bush and buried the bird there, covering the fresh dirt with a small pile of stones.

At midnight on Christmas Eve, just before the end of my shift, I heard gunshots ring out in Mexico. I stopped my vehicle at the top of a small hill and stood on the roof to watch the sparkling of fireworks along the southern horizon.

After returning home, I woke my mother, who had come to visit once more for the holiday, her eyes bleary with worry and sleep. We sat together in my empty living room, talking through the night-weary hours of the morning, drinking eggnog and stringing popcorn around an artificial tree. My mother asked about my shift. It was fine, I said. She asked if I was liking the work, if I was learning what I wanted. I knew what she was asking, but I didn’t have the energy to think of it, to weigh where I was against what had brought me there. The work isn’t really something to like, I told her curtly. There’s not a lot of time to sit around and reflect on things. A slow look of resignation came across my mother’s face. It’s my job, I told her, and I’m trying to get used to it, I’m trying to get good at it. I can figure out what that means later.

You know, my mother said, it’s not just your safety I worry about. I know how a person can become lost in a job, how the soul can buckle when placed within a structure. You asked me once how it felt looking back on my career. Well, the Park Service is an institution, an admirable one, but an institution nonetheless. If I’m honest, I can see now that I spent my career slowly losing a sense of purpose even though I was close to the outdoors, close to places I loved. You see, the government took my passion and bent it to its own purpose. I don’t want that for you.

I cut her off. I was too exhausted to consider my passion or sense of purpose, too afraid to tell my mother about the dreams of dead bodies and crumbling teeth, about the bird I had buried beneath stones, about my hands shaking at the wheel. Mom—I said—let’s open a present.

After dark, the scope truck spotted a group of twenty heading north toward the bombing range. The operator said that they were moving slowly, that it looked like there might be women and children among them. He guided us in and we quickly located their sign and then lost it again across a stretch of hard-packed desert pavement. We split up and combed the hillside, hunting for toe digs and kicked-over rocks. As I looked desperately for sign, I thought of the deadly expanses that stretched between here and the nearest highway, the nearest place that the group might stop for aid. On the walk back to our vehicle I became furious. There were supposed to be twenty of them, they were supposed to be slow, but still I couldn’t catch up, I couldn’t stay on the sign, I couldn’t even get close enough to hear them in the distance, and so now they remained out there in the desert—men, women, and children, entire families invisible and unheard—and I was powerless to help them, powerless to keep them from straying through the night.