“I want to talk about simulations,” I say. “But first, something else—your mother thought Jeanine would go after the factionless next. Obviously she was wrong—and I’m not sure why. It’s not like the Candor are battle ready or anything—”

“Well, think about it,” he says. “Think it through, like the Erudite.”

I give him a look.

“What?” he says. “If you can’t, the rest of us have no hope.”

“Fine,” I say. “Um . . . it had to be because Dauntless and Candor were the most logical targets. Because . . . the factionless are in multiple places, whereas we’re all in the same place.”

“Right,” he says. “Also, when Jeanine attacked Abnegation, she got all the Abnegation data. My mother told me that the Abnegation had documented the factionless Divergent populations, which means that after the attack, Jeanine must have found out that the proportion of Divergent among the factionless is higher than among the Candor. That makes them an illogical target.”

“All right. Then tell me about the serum again,” I say. “It has a few parts, right?”

“Two,” he says, nodding. “The transmitter and the liquid that induces the simulation. The transmitter communicates information to the brain from the computer, and vice versa, and the liquid alters the brain to put it in a simulation state.”

I nod. “And the transmitter only works for one simulation, right? What happens to it after that?”

“It dissolves,” he says. “As far as I know, the Erudite haven’t been able to develop a transmitter that lasts for more than one simulation, although the attack simulation lasted far longer than any simulation I’ve seen before.”

The words “as far as I know” stick in my mind. Jeanine has spent most of her adult life developing the serums. If she’s still hunting down the Divergent, she’s probably still obsessed with creating more advanced versions of the technology.

“What’s this about, Tris?” he says.

“Have you seen this yet?” I say, pointing at the bandage covering my shoulder.

“Not up close,” he says. “Uriah and I were hauling wounded Erudite up to the fourth floor all morning.”

I peel away the edge of the bandage, revealing the puncture wound—no longer bleeding, thankfully—and the patch of blue dye that doesn’t seem to be fading. Then I reach into my pocket and take out the needle that was buried in my arm.

“When they attacked, they weren’t trying to kill us. They were shooting us with these,” I say.

His hand touches the dyed skin around the puncture wound. I didn’t notice it before because it was happening right in front of me, but he looks different than he used to, during initiation. He’s let his facial hair grow in a little, and his hair is longer than I’ve ever seen it—dense enough to show me that it is brown, not black.

He takes the needle from me and taps the metal disc at the end of it. “This is probably hollow. It must have contained whatever that blue stuff in your arm is. What happened after you were shot?”

“They tossed these gas-spewing cylinders into the room, and everyone went unconscious. That is, everyone but Uriah and me and the other Divergent.”

Tobias doesn’t seem surprised. I narrow my eyes.

“Did you know that Uriah was Divergent?”

He shrugs. “Of course. I ran his simulations, too.”

“And you never told me?”

“Privileged information,” he says. “Dangerous information.”

I feel a flare of anger—how many things is he going to keep from me?—and try to stifle it. Of course he couldn’t tell me Uriah was Divergent. He was just respecting Uriah’s privacy. It makes sense.

I clear my throat. “You saved our lives, you know,” I say. “Eric was trying to hunt us down.”

“I think we’re past keeping track of who has saved whose life.” He looks at me for a few long seconds.

“Anyway,” I say to break the silence. “After we figured out that everyone was asleep, Uriah ran upstairs to warn the people who were up there, and I went to the second floor to figure out what was going on. Eric had all the Divergent by the elevators, and he was trying to figure out which of us he was going to take back with him. He said he was allowed to take two. I don’t know why he was going to take any.”

“Odd,” he says.

“Any ideas?”

“My guess is that the needle injected you with a transmitter,” he says, “and the gas was an aerosol version of the liquid that alters the brain. But why . . .” A crease appears between his eyebrows. “Oh. She put everyone to sleep to find out who the Divergent were.”

“You think that’s the only reason for shooting us with transmitters?”

He shakes his head, and his eyes lock on mine. Their blue is so dark and familiar that I feel like it could swallow me whole. For a moment I wish it would, so that I could escape this place and all that has happened.

“I think you’ve already figured it out,” he says, “but you want me to contradict you. And I’m not going to.”

“They’ve developed a long-lasting transmitter,” I say.

He nods.

“So now we’re all wired for multiple simulations,” I add. “As many as Jeanine wants, maybe.”

He nods again.

My next breath shakes on the way out of my mouth. “This is really bad, Tobias.”

In the hallway outside the interrogation room, he stops, leaning against the wall.

“So you attacked Eric,” he says. “Was that during the invasion? Or when you were by the elevators?”

“By the elevators,” I say.

“One thing I don’t understand,” he says. “You were downstairs. You could have just run away. But instead, you decided to dive into a crowd of armed Dauntless all by yourself. And I’m willing to bet you weren’t carrying a gun.”

I press my lips together.

“Is that true?” he demands.

“What makes you think I didn’t have a gun?” I scowl.

“You haven’t been able to touch a gun since the attack,” he says. “I understand why, with the whole Will thing, but—”

“That has nothing to do with it.”

“No?” He lifts his eyebrows.

“I did what I had to do.”

“Yeah. But now you should be done,” he says, pulling away from the wall to face me. Candor hallways are wide, wide enough for all the space I want to keep between us. “You should have stayed with the Amity. You should have stayed far away from all of this.”

“No, I shouldn’t have,” I say. “You think you know what’s best for me? You have no idea. I was going crazy with the Amity. Here I finally feel . . . sane again.”

“Which is odd, considering you are acting like a psychopath,” he says. “It’s not brave, choosing the position you were in yesterday. It’s beyond stupid—it’s suicidal. Don’t you have any regard for your own life?”

“Of course I do!” I retort. “I was trying to do something useful!”

For a few seconds he just stares at me.

“You’re more than Dauntless,” he says in a low voice. “But if you want to be just like them, hurling yourself into ridiculous situations for no reason and retaliating against your enemies without any regard for what’s ethical, go right ahead. I thought you were better than that, but maybe I was wrong!”

I clench my hands, my jaw.

“You shouldn’t insult the Dauntless,” I say. “They took you in when you had nowhere else to go. Trusted you with a good job. Gave you all your friends.”

I lean against the wall, my eyes on the floor. The tiles in the Merciless Mart are always black and white, and here they are in a checkered pattern. If I unfocus my eyes, I see exactly what the Candor don’t believe in—gray. Maybe Tobias and I don’t believe in it either. Not really.

I weigh too much, more than my frame can support, so much I should fall right through the floor.

“Tris.”

I keep staring.

“Tris.”

I finally look at him.

“I just don’t want to lose you.”

We stand there for a few minutes. I don’t say what I’m thinking, which is that he might be right. There is a part of me that wants to be lost, that struggles to join my parents and Will so that I don’t have to ache for them anymore. A part of me that wants to see whatever comes next.

“So you’re her brother?” says Lynn. “I guess we know who got the good genes.”

I laugh at the expression on Caleb’s face, his mouth drawn into a slight pucker and his eyes wide.

“When do you have to get back?” I say, nudging him with my elbow.

I bite into the sandwich Caleb got me from the cafeteria line. I am nervous to have him here, mixing the sad remains of my family life with the sad remains of my Dauntless life. What will he think of my friends, my faction? What will my faction think of him?

“Soon,” he says. “I don’t want anyone to worry.”

“I didn’t realize Susan had changed her name to ‘Anyone,’” I say, raising an eyebrow.

“Ha-ha,” he says, making a face at me.

Teasing between siblings should feel familiar, but it doesn’t for us. Abnegation discouraged anything that might make someone feel uncomfortable, and teasing was included.

I can feel how cautious we are with each other, now that we’re discovering a different way to relate in light of our new factions and our parents’ deaths. Every time I look at him, I realize that he’s the only family I have left and I feel desperate, desperate to keep him around, desperate to narrow the gap between us.

“Is Susan another Erudite defector?” says Lynn, stabbing a string bean with her fork. Uriah and Tobias are still in the lunch line, waiting behind two dozen Candor who are too busy bickering to get their food.

“No, she was our neighbor when we were kids. She’s Abnegation,” I say.

“And you’re involved with her?” she asks Caleb. “Don’t you think that’s kind of a stupid move? I mean, when all this is over, you’ll be in different factions, living in completely different places. . . .”

“Lynn,” Marlene says, touching her shoulder, “shut up, will you?”

Across the room, something blue catches my attention. Cara just walked in. I put down my sandwich, my appetite gone, and look up at her with my head lowered. She walks to the far corner of the cafeteria, where a few tables of Erudite refugees sit. Most of them have abandoned their blue clothes in favor of black-and-white ones, but they still wear their glasses. I try to focus on Caleb instead—but Caleb is watching the Erudite, too.

“I can’t go back to Erudite any more than they can,” says Caleb. “When this is over, I won’t have a faction.”

For the first time I notice how sad he looks when he talks about the Erudite. I didn’t realize how difficult the decision to leave them must have been for him.

“You could go sit with them,” I say, nodding toward the Erudite refugees.

“I don’t know them.” He shrugs. “I was only there for a month, remember?”

Uriah drops his tray on the table, scowling. “I overheard someone talking about Eric’s interrogation in the lunch line. Apparently he knew almost nothing about Jeanine’s plan.”

“What?” Lynn slaps her fork on the table. “How is that even possible?”

Uriah shrugs, and sits.

“I’m not surprised,” Caleb says.

Everyone stares at him.

“What?” He flushes. “It would be stupid to confide your entire plan to one person. It’s infinitely smarter to give little pieces of it to each person working with you. That way, if someone betrays you, the loss isn’t too great.”

“Oh,” says Uriah.

Lynn picks up her fork and starts eating again.

“I heard the Candor made ice cream,” says Marlene, twisting her head around to see the lunch line. “You know, as a kind of ‘it sucks we got attacked, but at least there are desserts’ thing.”

“I feel better already,” says Lynn dryly.

“It probably won’t be as good as Dauntless cake,” says Marlene mournfully. She sighs, and a strand of mousy brown hair falls in her eyes.

“We had good cake,” I tell Caleb.

“We had fizzy drinks,” he says.

“Ah, but did you have a ledge overlooking an underground river?” says Marlene, waggling her eyebrows. “Or a room where you faced all your nightmares at once?”

“No,” says Caleb, “and to be honest, I’m kind of okay with that.”

“Si-ssy,” sings Marlene.

“All your nightmares?” says Caleb, his eyes lighting up. “How does that work? I mean, are the nightmares produced by the computer or by your brain?”

“Oh God.” Lynn drops her head into her hands. “Here we go.”

Marlene launches into a description of the simulations, and I let her voice, and Caleb’s voice, wash over me as I finish my sandwich. Then, despite the clatter of forks and the roar of hundreds of conversations all around me, I rest my head on the table and fall asleep.

CHAPTER EIGHTEEN

“QUIET DOWN, EVERYONE!”

Jack Kang lifts his hands, and the crowd goes silent. That is a talent.

I stand among the crowd of Dauntless who got here late, when there were no seats left. A flash of light catches my eye—lightning. It’s not the best time to be meeting in a room with holes in the walls instead of windows, but this is the biggest room they have.

“I know many of you are confused and shaken by what happened yesterday,” Jack says. “I have heard many reports from a variety of perspectives, and have gotten a sense for what is straightforward and what requires more investigation.”