NO ONE PAID ANY attention to her when she stepped out onto the fifth floor. She hurried to the far end of the room and found a free computer and sat in front of it. Then she plugged in the drive and entered the numbers on the display.

A program seemed to detect the drive and automatically launch itself, then prompted her for a password. She tried all the ones she had used before: “Core,” “Cor,” and “Kore,” then “Persephone,” and finally “Hypatia.” The screen cleared and changed to Meret’s homepage.

She glanced down at the keyboard. It didn’t seem very different from the ones she was used to, though there were a few keys she didn’t recognize. She played around with them, figuring out what they did, and then called up the directory.

There were dozens of files, far too many to take in at once. At the head of the list was something called “Reminder.” Every other file was in alphabetical order; did Meret want her to look at this one especially?

She opened it. It was short, just a few lines. “Reminder: Sending an employee only a few hours into the past or future requires a great deal of modeling; in fact, as the intervals in time get smaller and smaller the problems of insertion and extraction grow proportionally greater. It is far easier to move an employee decades or even centuries. If an employee is in danger and must be extracted at once it is better to send him some years into the future. After he has been inserted into a safe tace, you will have time to calculate when and where you can reinsert him.

“Remember also that this method does not involve a key but is instead done remotely, from the fifth floor. This means that you will have to work out both the traveler’s beginning dates and his end dates from your station here. This is in contrast to travelers who use a key, whose time of extraction can be controlled from the past by that key and thus are open-ended. These two types of travel are called Closed and Open.”

Ann understood Meret’s meaning immediately, though the file was couched in such vague generalities she doubted if anyone in the company would get it. Meret was telling her that she had been the one to send Ann ahead in time, to 415, to get her out of danger while she calculated the safest way to return her to 391. Probably when Meret had gotten back from her assignment in Alexandria, before she had been sent to Kaphtor, she had looked through the archives and seen Ann on the camera feed, being attacked by the mob. And probably she had done exactly what Ann was doing, she had stolen moments on the computer, and had very little time in which to work. She had acted quickly, had sent Ann to 415 on the spur of the moment, maybe because they had discussed Hypatia’s death.

And maybe she had wondered, just a little bit, if Ann could help Hypatia, could save her from the mob that wanted to kill her. But some historical events, the company had taught, could not be changed, no matter how many people they sent to solve the problem.

It was no wonder, Ann thought, that she felt so much out of place, as if she didn’t belong in this timeline. She might have died, like Jerry, or survived and been left for dead, or been raped by the mob.

She shivered. This was the second time Meret had saved her life; it seemed she owed her for far more than just opening her eyes to the company’s misdeeds.

She had discovered the answer to a smaller puzzle as well. She’d wondered how she’d been moved without a key, and why there had been a gap of five hours between the time she’d left Alexandria in 391 and when she’d been returned. Now she realized it was probably because Meret had been working in a hurry and hadn’t had time to be precise. Meret’s information also meant that she didn’t need a key to travel now, a great relief, since she didn’t have any idea where to find one. Though it also meant she would have to program her beginning and end dates beforehand.

But why hadn’t the company found this evidence of Meret’s meddling? They had been determined to discover where Ann had gone during the time she was away; she couldn’t believe they hadn’t checked the feed from the camera, the same feed Meret had used.

She looked through the directory and found a file called “Videos,” clicked on it, and entered the time and place she was looking for. But although she found herself in Alexandria, along with film of Elias, Da Silva, and Zachery, there was nothing showing her and the mob at the library. Meret had somehow managed to erase it. She felt an extraordinary relief.

She studied the alphabetized list for other messages from Meret but found nothing. Perhaps they had been hidden to prevent the company from seeing them, but if so Meret had done too good a job of it; Ann couldn’t find them either.

She did find a manual for the launch room, though, a tutorial for new employees. She opened it and paged through, fascinated by the technology.

She learned that the time machine had its own internal timeline, that voyages to the past took place in strict chronological order. So that, according to this timeframe, Gregory’s assignment to the Spanish Inquisition had happened before his assignment to Kaphtor, even though, in the world’s chronology, he had appeared in Spain in 1506 and in Kaphtor around 1,500 years before Christ. The company had found it necessary to impose this timeline in order to, as the manual said, “keep everything from happening all at once. If all our assignments occurred at the same time, we would never know which assignments caused which results, and everything would be in chaos.”

She also discovered that the company could not travel into their own future, that they had no way of knowing how their manipulations had changed the world. Why, though, hadn’t someone come back from the future to visit them? The company was divided on the answer. One faction thought that this silence meant that they had failed, that no one had survived much beyond 2327. Another group argued that the people of the future had kept away on purpose, that they knew that by simply being there they could change the timelines, could affect the company’s project in negative ways. This claim had the virtue of optimism, of a belief that there would be a future, and that it was viable.

A loud commotion sounded at the door. “Ann Decker,” someone called. “Is she here?”

She looked up quickly. No one pointed her out; none of these people knew her. But men were fanning out through the room, and although she was at the far end someone would eventually reach her station. She erased her tracks through the computer, logged off, and grabbed the thumb drive.

Now what? She couldn’t head toward the door; one of the men would stop her, take away the drive. Arrest her for having it, probably. She was trapped.

No, there was one way out. She walked toward the room with the small launch pad, trying not to draw attention, to look as if she had important work to do. Once inside she closed the door and ran to the controls. The computer was already on, and set for 2327. She tapped the screen and hurried up onto the platform.

She felt the familiar time sickness, saw the piercing lights. She struggled to stay upright, to hold onto an awareness of her surroundings. When the nausea ended she saw that she was still in the launch room on the fifth floor, exactly where she had wanted to be. And the year was—she stepped off the platform and studied the computer—2327.

She opened the door and went outside. Once again no one paid any attention to her; everyone was focused on their own work. The computer workstations were where they had been in her own time, she saw. That made sense—people who traveled from one tace to another would want things to remain as familiar as possible. The machine she had used was occupied, though, and she went to a computer two stations down, far enough so that no one could peer over her shoulder.

She looked around her. The lights were more muted here, to save energy perhaps. Possibly in response to that the clothes were even brighter than in her tace, the colors more clashing. A lot of them were asymmetrical too, missing a sleeve or half a collar. Her own outfit, hastily put together, seemed even more out of place.

The keyboard looked more or less the same as the earlier one. She logged on, but she felt too worried about the men who had come looking for her to concentrate. When she hadn’t shown up at the debriefing Jerry had no doubt told Da Silva that he had seen her heading toward the elevator. They couldn’t know that she had the thumb drive, though, so they had almost certainly checked out the fifth floor just to be thorough. Maybe they’d thought she had snuck in with someone who had a key.

But it would probably never occur to them that she could use the time machine, and that she had gone into the future. They had such low opinions of their employees in the past, after all. And even if they thought to examine the machine, there was already an explanation for why it was set for the year 2327: someone had used it before her.

Still, they could have ways of finding her that she had never thought of. She might not have much time. So now what? she thought. What should she do with the brief window she did have?

She knew the answer to that, though; it seemed she had always known it. She had to find a way to change history back to what it had been—and to do so in a way that the company couldn’t change it back.

But she would have to go to a place where she already knew the language, and where her biome matched the existing bacteria. That meant she could only visit three time-frames, a pretty serious limitation. Or she could try some other tace, see how long she could survive there and how quickly she could learn the language.

Biomes, she thought, alarmed. She hadn’t had a swab for the time she found herself in now—could she be missing some vital bacteria? She didn’t feel ill, but there might be something here that would take a while to affect her. And all their teachers had said that the future was terribly polluted.

She should get to work, then. She searched the directory and found a tutorial for computer modeling.

It started off with Monte Carlo Markov chains, she saw, and she felt thankful that she had studied them earlier. But the tutorial grew more difficult to follow as she continued, and when she looked at her computer clock she saw that it had taken her twenty minutes to go through ten pages. And there were dozens of pages more, and those looked even harder.

She forced herself on, though, and twenty pages later she understood enough to think about modeling, about what events she could try to change. What if she went back, saw Trencavel, and persuaded him not to believe anything the angel said? She entered the variables she needed, looked carefully through the code for errors, and clicked Execute.

The computer returned a probability of her desired outcome at 57%. Not great, she thought. Even worse, a list of possible negative events had appeared at the bottom of the page, and one of them was the somewhat unnerving prediction that she had a chance of seeing her earlier self. A jumble of equations followed, but all she could understand from them was that meeting yourself was strongly counter-indicated, that it could snarl the timelines like a ball of yarn.

She stretched and glanced at the clock, which said 13:23. It was afternoon, and she was starting to feel hungry. Did they have a cafeteria here? More importantly, what about bathrooms?

The man at the workstation two down from her caught her eye and said something. The words flowed into each other, gliding over her like a stream. Did they even speak English here, or something close to it? “What?” she said.

“I said, are you just back from the tributaries?”

She had been able to pick out individual words that time, fortunately. “Oh. Yeah.”

“Good to be back at the headwaters, I bet.”

“Yeah.”

“What’s your name?”

She thought quickly. “Tarquina,” she said.

He laughed, though whether at the name or something else she didn’t know. At least he seemed to accept it.

“What’s yours?” she asked.

“Silas. Want to come for lunch?”

“Sure.”

He rounded up a few other people and they left their workstations and crowded into the elevator. Two of them used wheelchairs, and she remembered once again that her professors had talked about the high levels of radiation and pollution in the future. Did they have a lot of birth defects hern?

The cafeteria was on the first floor, the same place it had been in the past. The familiarity relieved her, made her feel as if the future might not be too different after all.

She followed the others to the end of the line. Then she saw the men and women working behind the counters and she stopped, disbelieving. They all looked the same, tall and thin, almost exactly like the man she called Joe had seen on the fifth floor.

“Some of the mockmeat, Joe,” Silas said, pointing to a tray of food she couldn’t identify.

Were they all named Joe? They had probably been bio-engineered, cloned from a single original. Someone who was good at repetitive tasks, maybe. Someone named Joe?

Charles had said they couldn’t give them consciousness, though. So the Joe on the fifth floor, the man who had worked so quickly at the computer—he was just a kind of machine. Weird.

A woman nudged her, and one of the Joes was looking at her quizzically. “Mockmeat, please,” she said, and he ladled it onto a plate and handed it to her.

Another Joe, this one female, asked her what she wanted to drink. Or would she be a Josephine? Ann pointed to a drink on another tray and said, “That one, please.”

“My, we are polite.”

It was the woman next to her, one of the people in a wheelchair. For a moment Ann didn’t understand what she meant. Then she realized that she had said “please” to the Joes, that probably no one used this sort of courtesy with them. “I’m just back from the tributaries,” she said. “They’re zany polite, where I was.”

“Are you?” the woman said. “What was your go?”

What did that mean? She guessed that “go” referred to an assignment. “Kaphtor. Crete, about four thousand years ago.”

“It sounds wonderful.”

“It was. Sunlight and oceans, and the gods and goddesses, Kore and Demeter …”

They were the same words Gregory had used, a long time ago. Hundreds of years ago, now. But the other woman said nothing in response to her mention of Kore.

To her relief she found she didn’t have to pay for her food; apparently the company still supplied free meals. She headed outside with the others, very conscious of the antique money in her purse.

There was something strange in the courtyard, something she couldn’t identify, though it raised all the hairs on the back of her neck. Then she saw that a great part of the city had been covered over, that a barely visible dome stretched out far above them and a few miles on either side. It dimmed the light around them; even things several yards away were darker.

And there were no shadows here. Something deep within her had responded to that, something atavistic. She felt a strong sense of wrongness, as if an essential part of the world had gone missing.

The others were clustering around a picnic table that hadn’t been there in her time. She hurried to join them. The woman she had talked to earlier rolled up next to her, at the end of the table.

“I’m Zarifa,” the woman said. “What’s your name?”

“Tarquina.”

She took a bite of the mockmeat. It was heavily salted, though it seemed to have no flavor beneath that. “The food was prob better where you were, am I right?” Zarifa said.

She nodded, started to answer. Instead she began to cough, and went on for a long time before she was able to stop. She took a deep breath, then swallowed half her drink in one gulp. It was only water, slightly salty tasting like the food.

“Not used to the fine ambience at the headwaters?” Silas asked.

She tried to smile. “Not yet, no.”

“It used to be even worse,” Zarifa said. “Before the go to Languedoc. Were you here for that timequake?”

Ann shook her head. So she and the others had been responsible for a slight improvement in the future.

“You’re so lucky,” Zarifa said, her voice lower now, almost a whisper. “We all want to go out to the tributaries, get away from this awful place, even if it’s just for an hour or two. It’s wrong to admit it, but I know all of them feel the same way.” She indicated the others at the table with her chin. “How did you manage to qualify?”

Ann shrugged. “I’m not all that sure, really.”

“Don’t be so modest,” Zarifa said. “You must be some kind of brain.”

She had sounded wistful. And probably she would qualify only for assignments to the twentieth century or later, where wheelchairs were more common.

Ann started to say something, then began to cough again. This time the fit went on for so long that Zarifa turned away and began to talk to the person on her other side.

Ann finished, then swallowed the rest of her water. Silas looked at her, a puzzled expression on his face. The people in this tace were used to the pollution, probably; they had to wonder why she was having so much trouble breathing.

“How did you know I was from the tributaries?” she said to Silas, to keep him from asking awkward questions.

“Are you kidding?” he said. “Who else would wear those clothes? Late twentieth century, am I right?”

Early twenty-first, she thought, but she nodded. She wanted him to know as little about her as possible.

Another cough began to tickle the back of her throat, and she stood. “I’m getting some more water,” she said.

To her alarm, the others began to laugh. “Went native, then?” one of them asked.

She had no idea what he meant. She sat back down anyway, knowing only that she had blundered somehow.

“They didn’t have rationing where you were, am I right?” someone else asked.

So that was it—they were only allowed one drink at lunch here. Still, she had to get inside, away from the bad air. “I’m going back to work,” she said, standing up again.

Silas’s puzzled expression had returned. She had made another misstep, but she couldn’t stop to figure out what she’d done. She had to get into the building before she started coughing again.

To her relief she found a bathroom near the cafeteria. The plumbing inside was the most unfamiliar thing she had encountered so far, probably designed to recycle human waste. It took her a while to figure it out, but finally she finished and washed her hands. She was so thirsty she sipped the water that came out of the tap, but it was full of salt, undrinkable. Then she went back up to the fifth floor.

She continued working on her modeling, barely stopping to greet Silas and the others when they came back. The day wore on. A long time later she heard a group of people shout in triumph, and a few minutes after that another group entered the room and hurried over to them, setting up their own portable computers.

“Do you think you can finish modeling this today?” one of them said. “The second shift comes on in two hours.”

“Sure,” someone else said.

She glanced at her clock. 18:07. So they worked long hours here, until eight in the evening. It looked as if their minds as well as their bodies had been damaged by the pollution, that only a few people were intelligent enough to do the work the company needed. And these poor saps had to take on twice as much, to make up for everyone else. No wonder TI had recruited people from her own time period.

That lack of competent people would explain Walker as well. The company had had to lower their standards, to hire employees who weren’t quite intelligent enough. And then, once Walker had joined the company, they would have found it impossible to dislodge her. In every tace Ann had seen the company had chosen hierarchies over democracies, had supported a strong person or group to rule over the great mass of people, from the Achaeans to Simon de Montfort. There was no reason to believe the company would not structure itself the same way—and Ann knew, from all her various jobs, that it was very easy to hide within this kind of organization, that responsibility could be spread around to different levels so that no one person ended up taking the blame. Walker’s blunders would never have come to the notice of upper management.

What about the pills the company had given her and the others, to make them more intelligent, able to learn faster? But maybe they didn’t work on the people in this tace, for one reason or another.

She shook her head. She should be working, not coming up with theories to explain the company.

What would happen when the second shift started? Someone would definitely notice if she stayed on; she would have to leave with everyone else. And what would she do then? Where could she go? She would have to get inside somewhere, or spend the night coughing her lungs out.

She turned back to the computer screen. She remembered her debriefing with Da Silva, and her speculation that the whole purpose of their assignment had been to make sure that Montfort survived. But what if Montfort had been killed at Carcassonne …

She typed in a few variables. 38%, the computer said. God, that was the worst yet. But in her timeline he hadn’t died in Carcassonne but in Toulouse, nine years later. She set up the modeling parameters again and hit return.

84%. She was close now, the closest she had come so far. She worked on refining the parameters, getting a higher score each time.

When she stopped to look at the clock she saw that it was already 19:38. She worked as quickly as she could, keeping an ear out for the next shift. Finally the computer returned a score of 95%.

Yes! she thought. The manual had cautioned against using anything under 98%, but she didn’t have time to refine her parameters further. And she was supposed to check her work with a holographic computer, one of the machines with visual modeling she had seen on her first visit, but she didn’t have time for that either. Anyway, all the holographic computers were taken.

She went back to the directory, intending to erase everything she had done that day. Suddenly she stopped, her attention drawn to a file called Employees.

She hesitated, then tapped it. It opened onto an alphabetized list. She scrolled down and found her name.

The first thing in her file was a letter from someone she had never heard of. “I’m writing from Local Year 1989, where I was sent to look for recruitment possibilities, children with no families or other attachments. To this end I’ve stationed myself at a local hospital. Yesterday I saw an ambulance bring in a newborn with dreadful wounds to her torso. I overheard one of the medical technicians say that her mother had given her up, and so of course I immediately thought of her as a possible. I managed to get a look at the intake form and find her address, then programmed a camera to go there twenty-four hours earlier. The footage from that camera is attached.”

Ann tapped the screen. Her hand was trembling. Here it was, the answer to the first question she had ever asked.

An empty garage appeared on the screen. The overhead door was open, the camera just outside it, looking in. A woman—no, a girl, around fourteen—ran through an adjoining door, screaming and crying. Her hair was tangled and matted with sweat, and she was naked from the waist down.

She was carrying a baby, a newborn. She stopped and looked around frantically. The camera followed her as she went to a workbench at the side of the garage, with a set of tools hanging above it. She put the baby down on the bench and grabbed a pair of scissors, then cut her umbilical cord with shaking hands.

Then she looked down at the baby. Her expression had changed, become strange, remote. She raised her hand and stabbed the baby with the scissors. She stopped, looked at the wound she had made, and then brought the scissors down again and again. Five times, hitting each of the familiar places with terrible precision.

No. Ann closed her eyes. No, no, no—that couldn’t have happened. She was watching something else, not her own birth.

“Stop it!” a voice said.

She opened her eyes and looked at the screen. A boy had come through the door. He grabbed the girl’s wrist and wrestled with her a while, then finally snatched the scissors away from her.

He was still shouting, though—“Stop it! Stop it!” The girl screamed over him, “My life is ruined! It’s ruined!”

Finally he seemed to realize that she had stopped, that he was holding the scissors. “Look,” he said. He was trying to sound calm, but his voice still held a trace of hysteria. “We’ll go inside, call an ambulance, get it to a hospital.”

“No! No, we can’t, they’ll arrest me. Look, look what I did.”

“But it’s—she’s bleeding. It’s a girl, look. You can’t just let her die.”

“What if we …”

The girl’s eyes fluttered closed and she began to fall. The boy was still holding the scissors, but he caught her with his other hand. He stood there for a long moment, in shock, Ann thought. Finally he laid the girl on the concrete floor, picked up the baby, put her down, and then went back into the house, still carrying the scissors.

The film picked up some moments later, with the arrival of two ambulances. Emergency crews ran into the garage and broke into two groups, one for the girl and the other for the baby. “Loss of blood …” someone around the girl murmured. “What the fuck …” someone else said.

Everyone was hurrying now, talking fast, doing things Ann couldn’t follow. After a while she noticed that the boy was missing, that he had left before the ambulances had arrived.

The girl was loaded into an ambulance and driven away. The camera showed a cluster of paramedics around the baby, near the workbench. One of them—a woman—was holding her tightly and rocking her. A white bandage was wound around the baby’s small torso.

“What name should I put on the form here?” someone asked.

“Shouldn’t we wait, see what the mother says?”

“I don’t think she wants anything to do with her.”

“Well, Jane Doe, then.”

“We should give her a real name—she’ll have a hard enough time as it is,” the woman holding the child said. “What about … Ann.” She looked up at the tools on the workbench. “Ann … Decker.”

Ann followed the woman’s gaze. There was some kind of drill there, heavy and complicated. Black and Decker, it said on the handle.

The woman carried the baby into the remaining ambulance and they drove off, and the film ended.

Ann stared at the screen for a long time. After a while she noticed that Silas had turned to look at her, an alarmed expression on his face. She had been whispering under her breath, she realized: “No. No. No.”

“What is it?” Silas asked.

“Nothing,” she said.

She would go back, she thought. She would set the computer for 1989, walk into that garage, grab the scissors out of that woman’s hand. Her mother. She was crying without making a sound now, thin tears running down her cheeks. She wiped them carefully, not wanting Silas to notice.

There had been adoptions that had not gone through because of her scars. She had overheard people talking about it, though no one had come right out and said anything to her. Prospective parents were horrified by them, or made queasy, even more so when no one could tell them who had attacked her, or why. The reason had been deliberately forgotten, Ann thought now, so that no one would ever have to tell her such a terrible story.

And after years of rejection she had become cynical, sure that no one would ever adopt her, and that had certainly not helped her chances. She had talked back to adults, made sarcastic comments far above her age level. She had set a fire in a foster parent’s basement once, though that had been more in the nature of an experiment.

How much different would her life have been if she had never had the scars? She had been teased in every new school she went to, especially in gym class and other places where she had to change clothes. She had told some students that she had fallen into barbed wire as a child, and a group of girls—rich, popular, spoiled—had taken to calling her Barbie.

She could have been adopted, she thought. Could have had a family, gone to college, worked somewhere besides a crappy computer repair shop. She could have been named for something besides a tool company—and for a moment her hatred of the woman who had given her that name blazed so hotly she thought that Silas could probably feel it, two workstations down.

All her life she had disliked feeling sorry for herself, though, and this was no exception. She had learned to rely on herself, to make her own rules. She started to plan, to work out the steps she would need. Go to the launch room, set the computer …

The modelers around her were logging out of their computers and picking up their belongings, saying goodbye and moving toward the door. Silas was looking at her with that same puzzled expression, no doubt wondering why she hadn’t shut down her own computer. There was no time to model probabilities; she would have to set the machine for 1989 and hope for the best.

But what about Core, and the reason Meret had sent her here? Should she fix her life, or fix the world?

The hell with the world, she thought. What had it ever done for her?