“‘Resetting’ is our word for widespread memory erasure,” David says. “It is what we do when the experiments that incorporate behavioral modification are in danger of falling apart. We did it when we first created each experiment that had a behavioral modification component, and the last one in Chicago was done a few generations before yours.” He gives me an odd smile. “Why did you think there was so much physical devastation in the factionless sector? There was an uprising, and we had to quell it as cleanly as possible.”

I sit stunned in my chair, picturing the broken roads and shattered windows and toppled streetlights in the factionless sector of the city, the destruction that is evident nowhere else—not even north of the bridge, where the buildings are empty but seem to have been vacated peacefully. I always just took the broken-down sectors of Chicago in stride, as evidence of what happens when people are without community. I never dreamed that they were the result of an uprising—and a subsequent resetting.

I feel sick with anger. That they want to stop a revolution, not to save lives, but to save their precious experiment, would be enough. But why do they believe they have the right to rip people’s memories, their identities, out of their heads, just because it’s convenient for them?

But of course, I know the answer to that question. To them, the people in our city are just containers of genetic material—just GDs, valuable for the corrected genes they pass on, and not for the brains in their heads or the hearts in their chests.

“When?” one of the council members says.

“Within the next forty-eight hours,” David says.

Everyone nods as if this is sensible.

I remember what he said to me in his office. If we are going to win this fight against genetic damage, we will need to make sacrifices. You understand that, don’t you? I should have known, then, that he would gladly trade thousands of GD memories—lives—for control of the experiments. That he would trade them without even thinking of alternatives—without feeling like he needed to bother to save them.

They’re damaged, after all.

CHAPTER THIRTY-EIGHT

TOBIAS

I PROP UP my shoe on the edge of Tris’s bed and tighten the laces. Through the large windows I see afternoon light winking in the side panels of the parked airplanes on the landing strip. GDs in green suits walk across the wings and crawl under the noses, checking the planes before takeoff.

“How’s your project with Matthew going?” I say to Cara, who is two beds away. Tris let Cara, Caleb, and Matthew test their new truth serum on her this morning, but I haven’t seen her since then.

Cara is pushing a brush through her hair. She glances around the room to make sure it’s empty before she answers. “Not well. So far Tris was immune to the new version of the serum we created—it had no effect whatsoever. It’s very strange that a person’s genes would make them so resistant to mind manipulation of any kind.”

“Maybe it’s not her genes,” I say, shrugging. I switch feet. “Maybe it’s some kind of superhuman stubbornness.”

“Oh, are we at the insult part of the breakup?” she says. “Because I got in a lot of practice after what happened with Will. I have several choice things to say about her nose.”

“We didn’t break up.” I grin. “But it’s nice to know you have such warm feelings for my girlfriend.”

“I apologize, I don’t know why I jumped to that conclusion.” Cara’s cheeks flush. “My feelings toward your girlfriend are mixed, yes, but for the most part I have a lot of respect for her.”

“I know. I was just kidding. It’s nice to see you get flustered every once in a while.”

Cara glares at me.

“Besides,” I say, “what’s wrong with her nose?”

The door to the dormitory opens, and Tris walks in, hair unkempt and eyes wild. It unsettles me to see her so agitated, like the ground I’m standing on is no longer solid. I get up and smooth my hand over her hair to put it back into place. “What happened?” I say, my hand coming to rest on her shoulder.

“Council meeting,” Tris says. She covers my hand with hers, briefly, then sits on one of the beds, her hands dangling between her knees.

“I hate to be repetitive,” Cara says, “but . . . what happened?”

Tris shakes her head like she’s trying to shake the dust out of it. “The council has made plans. Big ones.”

She tells us, in fits and starts, about the council’s plan to reset the experiments. As she speaks she wedges her hands under her legs and presses forward into them until her wrists turn red.

When she finishes I move to sit beside her, putting my arm across her shoulders. I look out the window, at the planes perched on the runway, gleaming and poised for flight. In less than two days those planes will probably drop the memory serum virus over the experiments.

Cara says to Tris, “What do you intend to do about it?”

“I don’t know,” Tris says. “I feel like I don’t know what’s right anymore.”

They’re similar, Cara and Tris, two women sharpened by loss. The difference is that Cara’s pain has made her certain of everything, and Tris has guarded her uncertainty, protected it, despite all she’s been through. She still approaches everything with a question instead of an answer. It is something I admire about her—something I should probably admire more.

For a few seconds we stew in silence, and I follow the path of my thoughts as they turn over and over one another.

“They can’t do this,” I say. “They can’t erase everyone. They shouldn’t have the power to do that.” I pause. “All I can think is that this would be so much easier if we were dealing with a completely different set of people who could actually see reason. Then we might be able to find a balance between protecting the experiments and opening themselves up to other possibilities.”

“Maybe we should import a new group of scientists,” Cara says, sighing. “And discard the old ones.”

Tris’s face twists, and she touches a hand to her forehead, as if rubbing out some brief and inconvenient pain. “No,” she says. “We don’t even need to do that.”

She looks up at me, her bright eyes holding me still.

“Memory serum,” she says. “Alan and Matthew came up with a way to make the serums behave like viruses, so they could spread through an entire population without injecting everyone. That’s how they’re planning to reset the experiments. But we could reset them.” She speaks faster as the idea takes shape in her mind, and her excitement is contagious; it bubbles inside me like the idea is mine and not hers. But to me it doesn’t feel like she’s suggesting a solution to our problem. It feels like she’s suggesting that we cause yet another problem. “Reset the Bureau, and reprogram them without the propaganda, without the disdain for GDs. Then they’ll never risk the memories of the people in the experiments again. The danger will be gone forever.”

Cara raises her eyebrows. “Wouldn’t erasing their memories also erase all of their knowledge? Thus rendering them useless?”

“I don’t know. I think there’s a way to target memories, depending on where the knowledge is stored in the brain, otherwise the first faction members wouldn’t have known how to speak or tie their shoes or anything.” Tris comes to her feet. “We should ask Matthew. He knows how it works better than I do.”

I get up too, putting myself in her path. The streaks of sun caught on the airplane wings blind me so I can’t see her face.

“Tris,” I say. “Wait. You really want to erase the memories of a whole population against their will? That’s the same thing they’re planning to do to our friends and family.”

I shield my eyes from the sun to see her cold look—the expression I saw in my mind even before I looked at her. She looks older to me than she ever has, stern and tough and worn by time. I feel that way, too.

“These people have no regard for human life,” she says. “They’re about to wipe the memories of all our friends and neighbors. They’re responsible for the deaths of a large majority of our old faction.” She sidesteps me and marches toward the door. “I think they’re lucky I’m not going to kill them.”

CHAPTER THIRTY-NINE

TRIS

MATTHEW CLASPS HIS hands behind his back.

“No, no, the serum doesn’t erase all of a person’s knowledge,” he says. “Do you think we would design a serum that makes people forget how to speak or walk?” He shakes his head. “It targets explicit memories, like your name, where you grew up, your first teacher’s name, and leaves implicit memories—like how to speak or tie your shoes or ride a bicycle—untouched.”

“Interesting,” Cara says. “That actually works?”

Tobias and I exchange a look. There’s nothing like a conversation between an Erudite and someone who may as well be an Erudite. Cara and Matthew are standing too close together, and the longer they talk, the more hand gestures they make.

“Inevitably, some important memories will be lost,” Matthew says. “But if we have a record of people’s scientific discoveries or histories, they can relearn them in the hazy period after their memories are erased. People are very pliable then.”

I lean against the wall.

“Wait,” I say. “If the Bureau is going to load all of those planes with the memory serum virus to reset the experiments, will there be any serum left to use against the compound?”

“We’ll have to get it first,” Matthew says. “In less than forty-eight hours.”

Cara doesn’t appear to hear what I said. “After you erase their memories, won’t you have to program them with new memories? How does that work?”

“We just have to reteach them. As I said, people tend to be disoriented for a few days after being reset, which means they’ll be easier to control.” Matthew sits, and spins in his chair once. “We can just give them a new history class. One that teaches facts rather than propaganda.”

“We could use the fringe’s slide show to supplement a basic history lesson,” I say. “They have photographs of a war caused by GPs.”

“Great.” Matthew nods. “Big problem, though. The memory serum virus is in the Weapons Lab. The one Nita just tried—and failed—to break into.”

“Christina and I were supposed to talk to Reggie,” Tobias says, “but I think, given this new plan, we should talk to Nita instead.”

“I think you’re right,” I say. “Let’s go find out where she went wrong.”

When I first arrived here, I felt like the compound was huge and unknowable. Now I don’t even have to consult the signs to remember how to get to the hospital, and neither does Tobias, who keeps stride with me on the way. It’s strange how time can make a place shrink, make its strangeness ordinary.

We don’t say anything to each other, though I can feel a conversation brewing between us. Finally I decide to ask.

“What’s wrong?” I say. “You hardly said anything during the meeting.”

“I just . . .” He shakes his head. “I’m not sure this is the right thing to do. They want to erase our friends’ memories, so we decide to erase theirs?”

I turn to him and touch his shoulders lightly. “Tobias, we have forty-eight hours to stop them. If you can think of any other idea, anything else that could save our city, I’m open to it.”

“I can’t.” His dark blue eyes look defeated, sad. “But we’re acting out of desperation to save something that’s important to us—just like the Bureau is. What’s the difference?”

“The difference is what’s right,” I say firmly. “The people in the city, as a whole, are innocent. The people in the Bureau, who supplied Jeanine with the attack simulation, are not innocent.”

His mouth puckers, and I can tell he doesn’t completely buy it.

I sigh. “It’s not a perfect situation. But when you have to choose between two bad options, you pick the one that saves the people you love and believe in most. You just do. Okay?”

He reaches for my hand, his hand warm and strong. “Okay.”

“Tris!” Christina pushes through the swinging doors to the hospital and jogs toward us. Peter is on her heels, his dark hair combed smoothly to the side.

At first I think she’s excited, and I feel a swell of hope—what if Uriah is awake?

But the closer she gets, the more obvious it is that she isn’t excited. She’s frantic. Peter lingers behind her, his arms crossed.

“I just spoke to one of the doctors,” she says, breathless. “The doctor says Uriah’s not going to wake up. Something about . . . no brain waves.”

A weight settles on my shoulders. I knew, of course, that Uriah might never wake up. But the hope that kept the grief at bay is dwindling, slipping away with each word she speaks.

“They were going to take him off life support right away, but I pleaded with them.” She wipes one of her eyes fiercely with the heel of her hand, catching a tear before it falls. “Finally the doctor said he would give me four days. So I can tell his family.”

His family. Zeke is still in the city, and so is their Dauntless mother. It never occurred to me before that they don’t know what happened to him, and we never bothered to tell them, because we were all so focused on—

“They’re going to reset the city in forty-eight hours,” I say suddenly, and I grab Tobias’s arm. He looks stunned. “If we can’t stop them, that means Zeke and his mother will forget him.”

They’ll forget him before they have a chance to say good-bye to him. It will be like he never existed.