An explosion rippled across the field, sending up waves of black smoke. Victor slammed into the ground, fingers curling around his rifle.

“What happened?” Evie’s voice crackled in his ear. “The map just lit up!”

“Orvo saw me,” Victor muttered, hunched down low in the tall golden grasses. The motion sensor display in his HUD monocle blinked rapidly. Saskia was approaching.

Victor scrambled to his feet and ran along the wall of fire, coughing against the smoke. He ducked his head down, hoping the flames would be enough to keep him hidden from the watchful digital eye of Orvo, the AI that currently had them trapped here in the shadow of Hestia V, the planet they were orbiting.

“Victor, what are you doing?” Evie said. “Saskia’s headed toward you. That was the plan.”

“Yeah, but the field is burning!” He slowed to a jog, crouching down beneath the black clouds of smoke pouring off the smoldering grasses. He could just make out Saskia through the haze, a slim figure barreling toward him with a battle rifle slung over her shoulder.

“I see her,” he said to Evie. Then he took a deep breath and launched himself over the low-burning fire, feet pounding as he moved to intersect with Saskia.

“He can see us!” he bellowed, cupping his hands around his mouth. “Turn around!”

Saskia faltered, lifted her rifle. Heat rolled across the prairie in waves, thick and choking.

“Turn back!” he shouted, just as another swell of heat exploded out of the dirt behind him. He lost his footing and plunged forward. Saskia caught him in one smooth movement, dragging him toward the outcropping of rocks they’d been using as a shelter.

“Victor!” Evie shrieked. “Tell me you’re okay.”

“I’m fine,” Victor muttered. “We’re getting the hell out of here.”

“You were able to get ahold of Evie?” Saskia asked, glancing at him out of the corner of her eye as they tore through the waist-high grasses.

“Yeah. She has no idea where she is either.”

Saskia groaned, shaking her head. The shelter loomed up in the distance, the rocks a faint promise of safety. And failure.

Victor really thought his plan would have worked. Keep low in the grasses, get to the comm station down by the creek so Evie could send him the map. But Orvo had spotted him anyway.

At least Saskia wasn’t pulling any kind of I-told-you-so. Dorian probably would, though.

They darted through the gap in the rocks and into their makeshift shelter, where Dorian was crouched over a comm pad that emitted a glowing terrain map of the prairie.

“Knew it wouldn’t work,” he said without glancing up from the map.

Victor rolled his eyes.

“I’m thinking he’s got a camera—here.” Dorian enlarged the holo and pointed with one finger. The map gleamed with thatched white lines. The fire. “Both times the flames went up, you were in this area.” He circled with his finger.

“So we try again,” Victor said. “And avoid it.”

Saskia glanced at him. “There could be more cameras.”

Dorian tilted his head, shrugging a little. “Maybe. We know we’ve got a clear path here”—he traced his finger along the map, cutting straight through the flames—“but out here? No idea.” He waved his hand around wildly. “And we still aren’t sure how far it is to Evie.”

Victor slumped back, arms crossed over his chest, thoughts whirring. Saskia crouched down beside Dorian and frowned at the map. All Evie knew was that she was trapped in some kind of structure—no windows, the door barred. While the three of them had been trying to figure out the best way to evade Orvo, she had been hacking away furiously on the computer ONI had left in the room for her. It was the one tether between her and the rest of the group—at least, it had become one, once Victor managed to scrounge up the comm pad Dorian was currently using to create their map.

Two days ago, the four of them had learned they would be playing Capture the Flag. It was a huge surprise when it turned out Evie was the flag.

Orvo is toying with us, Victor thought. Everything seemed easy on the surface—a simple game, Evie locked up with her biggest strength. But the game had split them up, and Evie hadn’t been able to highlight her location, no matter how deep she went into the base’s systems.

Victor crawled forward, studying the map. Simple on the surface. Just like their path across the prairie. He should have known better.

Dorian sighed and tapped the comm, shrinking the map down. Dust from the rocks flitted around in its wake.

“Now what?” he asked. “Clearly, charging across the prairie isn’t going to work.”

Evie’s biggest strength, Victor thought. Simple on the surface.

“The comm pad,” he blurted. “The answer’s on there.”

Dorian rolled his eyes.

“No,” Victor said. “Listen.” He glanced over at Saskia, and she nodded at him, eyes bright with encouragement. He felt a little flutter of his old crush and threw her a big grin. Then he turned back to Dorian. “Everything keeps seeming like it’s going to be easy, right, but there’s some twist. They tell us we’re playing Capture the Flag—well, we’ve done that before, no big deal, right? Except—”

“Except they split us up,” Saskia said.

“And gave Evie a computer. Like, straight up gave her one. But it hasn’t been any help, other than us talking to each other.”

“What are you getting at?” Dorian said.

Victor pointed at the comm. “They’re forcing us to play against our strengths. Orvo knows what we’re going to do, and created a puzzle that challenges those instincts.”

He sat back, triumphant. Dorian just blinked at him.

“So what does that have to do with the comm pad?” he asked.

Victor sighed. “Don’t you get it? Saskia knows the weapons, you’re the terrain guy, I’m—” He gestured, hoping one of them would say it for him. He was the one willing to blaze across the prairie—to do whatever it took to get the mission done. Ever since Meridian, he’d gotten braver.

“The muscle?” Saskia said uncertainly.

“Whatever. None of us are hackers, really, the way Evie is. So that’s where the answer is.” He nodded at the comm pad.

“It makes sense,” Saskia said carefully. “It seems like something Orvo would do.”

It seemed like something ONI would do too. None of the training Victor and the rest of them had received on the UNSC military base had been straightforward. Not from the moment they arrived. But it had been useful. Victor couldn’t deny that.

“Well, get Evie on your HUD,” Dorian said. “Have her walk us through it.”

Victor wondered if getting in touch with Evie had been part of Orvo’s plan. Hard to say.

“Evie?” he said into the microphone. The HUD on his monocle flickered, and then Evie’s voice came through, striated with static.

“What happened?” she asked. “Is everyone okay?”

“We’re all fine,” Victor confirmed, switching on the speaker so all three of them could hear her responses. “We think the key to finding you is in this comm pad we scrounged up. The thing is, we’re going to have to go in and look around, and you’re—”

“Stuck in a tin can.” She laughed. “Seems about right. What are you thinking it’s going to be?”

Victor glanced at the others.

“The map,” Dorian said suddenly. “We both have one, right?”

“Yeah,” added Victor. “And Evie was able to see the explosions live.”

“Bring it up,” Evie said. “I’m doing the same on my end.”

The map materialized in the air above them. The fires still lit up white hot on the holo, crisscrossing the terrain.

“Tell me what you see,” Evie said. “Let’s make sure it’s the same.”

Dorian’s eyes flicked across the map. “We’ve got the fires. The prairie. Basically what we can see if we look out past the rocks.”

“Are the rocks marked? I can see them on mine.”

“Yes,” Saskia said, pointing at a bright dot in the bottom of the corner of the holo.

But Dorian shook his head. “That’s not the rocks; that’s our location. I could track you running across the field earlier. Is that what you’re seeing, Evie?”

“No,” she said, and Victor felt a jolt in his chest. We’re getting somewhere. “This is stationary. I can’t actually see where you guys are.” The line went quiet.

“What other differences are there?” Saskia said. “Our map doesn’t have much of anything on it. Just stuff we’ve already discovered.”

“Except for the rocks,” Dorian said.

Simple on the surface, Victor thought. But maybe things could be complicated on the surface too.

“She’s under us,” he blurted out. “Her map isn’t marking the rocks; it’s marking her location—”

Gunfire tore across their sanctuary—dirt and chunks of stone exploding into the air. Victor shouted and dove for cover, scrambling toward the edge. He could hear Saskia gasping behind him and Dorian cursing. Victor heaved himself out from between the rocks and helped pull Saskia out after him. The air was still thick with ash and smoke.

“Well, I think you might be onto something.” Dorian emerged from cover, his face streaked with dirt. “How did we not see those guns in there?”

“They came out of the rocks,” Saskia said. “The rocks must have been decoys. Artificial.”

Victor groaned. Already he could hear Orvo’s condescending debrief: You children shouldn’t be so trusting.

Evie’s voice spilled through the speaker. “—come in. Victor? Dorian?”

“We’re here.” Victor stared at the rocks.

“I heard gunfire,” she said. “Not over the headset. From—outside.”

Immediately, the guns started blazing again, light and dust exploding from the outcropping.

Saskia reached over and grabbed Victor’s helmet and then stomped on the receiver with her heavy booted foot.

“What the hell!” Victor sputtered.

“That’s how Orvo is listening in,” she said. “Or maybe just programmed the guns to react to key words. Either way, no more field helmet.”

“I’m going to get charged for that thing,” Victor ground out.

“Sorry.” She didn’t sound sorry, though. “The turrets on the fence back in Brume-sur-Mer had been like that. Programmed to react to certain sounds.”

“Fine!” Victor said, throwing his hands in the air. “But how do we know there aren’t any sensors down there? You said yourself the rocks were probably fake.”

“Because Orvo didn’t want us to be able to talk with Evie,” Dorian said. “Of course there are sensors down there: They’ve been monitoring us the whole time. But this was about us bending the rules.”

The gunfire stopped. Victor’s ears rang in the silence.

Dorian leaned over the rocks. “Isn’t that right, Orvo? You didn’t want us doing anything you hadn’t planned?”

No answer save for the crackle of fires in the distance.

Saskia knelt at the rocks. “We need to figure out how to get to Evie,” she said.

Nothing happened—no gunfire, no actual fire, nothing.

She glanced at Victor over her shoulder. “Told you.” She smiled.

Victor shrugged. “Fair enough.”

“So now what?” Dorian asked. “We scoured the rocks earlier. There was no sign of an entrance.”

“Maybe it’s not in the rocks themselves,” Saskia said. “We didn’t look closely enough at the surrounding land.”

Dorian considered this, shrugged.

“Fan out,” Victor said. “See what we can find. And be careful. I imagine Orvo isn’t going to let us get to Evie that easily.”

The other two nodded. Saskia pulled her pistol out of its holster and moved north. Dorian went west. And Victor went east. The prairies were still burning to the south. He only hoped the entrance wasn’t hidden under the flames.

Victor pushed through the waist-high grasses, hitting at them with the butt of his rifle so that he could see the strip of dry dirt beneath. Hot, smoky wind blew up from the fires, and Victor wiped the sweat from his forehead. Hestia V floated pale in the sky. On the other side of it was Meridian, Victor’s home. On the other side of Hestia V was the Covenant.

Victor shook the thoughts away; he had to focus on finding the entrance and getting to Evie. Doing well in their training here on Tuomi Base was the only way he was getting back to Meridian, to Brume-sur-Mer.

Suddenly, plasma fire ripped across the prairie. Victor jerked around, rifle raised and ready, aimed in the direction of the sound. North.

Saskia was firing her pistol into a hulking rumble of machinery, its curved, insect-like lines familiar and terrifying. For a moment, Victor was seized with a wild panic—the Covenant had found them.

But then Saskia called out, “It’s guarding the entrance! A little help?”

The entrance. ONI must have reconfigured a Covenant Locust—one of their automated, weapon-mounted walkers—for training. Victor raced forward, slicing through the grass. Dorian was headed toward them as well, a dark speck in the distance.

Saskia’s pistol clicked, and she tossed it aside. Pulling her rifle around on its strap, she fired it at the turret, already charging up with a pale pink light.

Victor fired off a round from his rifle, not that it did any good. Plasma sliced through the air and ignited the grasses with a plume of smoke. Saskia vanished behind the fire.

“Saskia!” Victor shouted, pumping his legs harder. The turret on the Locust tilted toward him, and he lifted his gun and fired off three shots before the plasma beam shimmered hotly through the air. He dove to the ground, rolling through the grasses.

There was a hole, big enough that the Locust must have crawled out of it. But there were stairs too.

His heart surged. They’d found it. But knowing Orvo, they were going to have to take out this Locust before they would safely be able to enter the structure. Good thing it was something they’d done before.

“Victor.” It was Saskia, emerging from the grass. Dirt smudged her face. “Where’s Dorian?”

“I saw him—”

An explosion rang out, fire and plasma erupting over the prairie. Victor slammed into the ground, his ears ringing. Everything sounded fuzzy and far away. But the Locust had toppled, three of its four armored legs now nothing but black chunks. The Locust’s cannon housing had been neutralized, and it now hung at an angle, its muzzle pointed into the ground.

On the other side of the smoke was Dorian, holding up his assault rifle and grinning.

“Got it!” he called.

Victor rolled his eyes. Saskia laughed, crawling shakily to her feet. “You learned that from me.”

Dorian grinned. “Right into the ventilation shaft,” he said.

“We’re not there yet,” Victor said, trudging over to where Dorian stood. Black ash flaked off the remains of the machine and trailed through the air, stinging Victor’s eyes. He refilled the magazine on his rifle and then edged toward the hole in the ground. Metal stairs gleamed, shining and out of place among the smoke and the grass. Victor watched them warily.

“You know Orvo has something else planned for us,” Saskia said in a low voice.

Victor nodded. “I’ll be the scout.”

The three of them moved forward. Victor pressed one foot lightly on the top stair, then followed with the rest of his weight. Nothing happened. He moved down, gun up and ready, descending into the gleaming underground room. Lights blinked in the walls: cameras. Orvo wanted them to know they were being watched.

“Clear!” Victor yelled out when he touched down at the base of the stairs. He swept his gaze around. The walls were smooth. No sign of a door. He thought of the wall that had surrounded Saskia’s house back in Brume-sur-Mer, the way the gate had materialized with her touch.

“I think it’s the same tech as your parents’ home defense system,” he said when she and Dorian had made it in. “Door hidden in the wall.”

Saskia frowned. “If it’s like the defense system at my house, then you have to know where the door is in order to access it. And I’m sure there’s a code.”

Once again, they needed Evie’s hacking skills. He sighed. “Too bad you stomped on my HUD.”

Saskia gave him a sideways look. “Even if we had it, I bet those things wouldn’t have let us get down here.” She jerked her chin at the wall. “You can actually see the guns here.”

“She’s right,” Dorian said, and she was. Dark circles ringed around the top of the walls, peering down at them. Muzzles.

“I bet we can still get to Evie, though.” And with that, Dorian marched up to the far wall, the one, Victor realized, that was closest to the rock outcropping. Then he lifted his gun and banged the butt hard against the wall.

“Evie!” he shouted. “You hear us?”

Silence. Then:

A faint tapping. Two slow taps, three quick, over and over again in an unmistakable pattern.

Saskia shouldered her gun and moved up to the wall, leaning close, eyes half-closed, listening. She pressed one hand against the wall, slid it along. Then, abruptly, a holographic keypad materialized.

“Found it!” she said.

“What’s the code?” Victor said.

The tapping was still echoing from inside the wall. Two slow taps, three quick.

Saskia pressed the two, then the three. Nothing. She tried again. Still nothing.

“Dammit,” Dorian muttered.

The tapping stopped. The silence buzzed in Victor’s ears.

Then it picked up again. The same tempo, all quick: one-two-three-four-five. A pause. One-two-three-four-five.

Saskia’s face lit up. “Got it,” she whispered, pressing the five key.

Immediately, the keypad vanished and a doorway slid open, revealing a narrow room and, at its center, Evie, already leaping to her feet and rushing toward them.

“I can’t believe that worked!” she cried. “They had me playing these dumb puzzles, and the answers were always two, three, five.” She laughed and threw her arm around Saskia in a quick friendly squeeze.

“Congratulations.” Orvo’s deep, sonorous voice echoed through the room. “You have successfully completed the exercise. Completion time nine point seven hours. Please report to Commander Pereira immediately for debriefing.”

All four of them groaned. “We don’t even get to clean up?” Dorian yelled.

“No,” Orvo said, almost cheerfully. “She wants to speak with you while the exercise is still fresh in your minds.”

“Never ends around here,” Dorian said, but he headed toward the stairs, just like the rest of them.