“Control room people said most of them have taken up residence north of the river, near the Hancock building,” Amar says. “Feel like going zip lining?”

“Absolutely not,” I say.

Amar laughs.

It takes us another hour to get close. Only when I see the Hancock building in the distance do I start to feel nervous.

“Um . . . Amar?” Christina says from the back. “I hate to say this, but I really need to stop. And . . . you know. Pee.”

“Right now?” Amar says.

“Yeah. It came on all of a sudden.”

He sighs, but pulls the truck over to the side of the road.

“You guys stay here, and don’t look!” Christina says as she gets out.

I watch her silhouette move to the back of the truck, and wait. All I feel when she slashes the tires is a slight bounce in the truck, so small I’m sure I only felt it because I was waiting for it. When Christina gets back in, brushing snowflakes from her jacket, she wears a small smile.

Sometimes, all it takes to save people from a terrible fate is one person willing to do something about it. Even if that “something” is a fake bathroom break.

Amar drives for a few more minutes before anything happens. Then the truck shudders and starts to bounce like we’re going over bumps.

“Shit,” Amar says, scowling at the speedometer. “I can’t believe this.”

“Flat?” I say.

“Yeah.” He sighs, and eases on the brakes so the car slips to a stop by the side of the road.

“I’ll check it,” I say. I jump down from the passenger’s seat and walk to the back of the truck. The back tires are completely flat, flayed by the knife Christina brought with her. I peer through the back windows to make sure there’s only one spare tire, then return to my open door to give the news.

“Both back tires are flat and we only have one spare,” I say. “We’re going to have to abandon the truck and get a new one.”

“Shit!” Amar smacks the steering wheel. “We don’t have time for this. We have to make sure Zeke and his mother and Christina’s family are all inoculated before the memory serum is released, or they’ll be useless.”

“Calm down,” I say. “I know where we can find another vehicle. Why don’t you guys keep going on foot and I’ll go find something to drive?”

Amar’s expression brightens. “Good idea.”

Before moving away from the truck I make sure that there are bullets in my gun, even though I’m not sure if I’ll need them. Everyone piles out of the truck, Amar shivering in the cold and bouncing on his toes.

I check my watch. “So you need to inoculate them by what time?”

“George’s schedule says we’ve got an hour before we reset the city,” Amar says, checking his watch too, to make sure. “If you want us to spare Zeke and his mother the grief and let them get reset, I wouldn’t blame you. I’ll do it if you need me to.”

I shake my head. “Couldn’t do that. They wouldn’t be in pain, but it wouldn’t be real.”

“As I’ve always said,” Amar says, smiling, “once a Stiff, always a Stiff.”

“Can you . . . not tell them what happened? Just until I get there,” I say. “Just inoculate them? I want to be the one who tells them.”

Amar’s smile shrinks a little. “Sure. Of course.”

My shoes are already soaked through from checking the tires, and my feet ache when they touch the cold ground again. I’m about to walk away from the truck when Peter speaks up.

“I’m coming with you,” he says.

“What? Why?” I glare at him.

“You might need help finding a truck,” he says. “It’s a big city.”

I look at Amar, who shrugs. “Man’s got a point.”

Peter leans in closer and speaks quietly, so only I can hear. “And if you don’t want me to tell him you’re planning something, you won’t object.”

His eyes drift to my jacket pocket, where the memory serum is.

I sigh. “Fine. But you do what I say.”

I watch Amar and Christina walk away without us, heading toward the Hancock building. Once they’re too far away to see us, I take a few steps back, slipping my hand into my pocket to protect the vial.

“I’m not going to look for a truck,” I say. “You might as well know that now. Are you going to help me with what I’m doing, or do I have to shoot you?”

“Depends what you’re doing.”

It’s hard to come up with an answer when I’m not even sure. I stand facing the Hancock building. To my right are the factionless, Evelyn, and her collection of death serum. To my left are the Allegiant, Marcus, and the insurrection plan.

Where do I have the greatest influence? Where can I make the biggest difference? Those are the questions I should be asking myself. Instead I am asking myself whose destruction I am more desperate for.

“I’m going to stop a revolution,” I say.

I turn right, and Peter follows me.

CHAPTER FORTY-FIVE

TRIS

MY BROTHER STANDS behind the microscope, his eye pressed to the eyepiece. The light in the microscope platform casts strange shadows on his face, making him look years older.

“This is definitely it,” he says. “The attack simulation serum, I mean. No question.”

“It’s always good to have another person verify,” Matthew says.

I am standing with my brother in the hours before he dies. And he is analyzing serums. It’s so stupid.

I know why Caleb wanted to come here: to make sure that he was giving his life for a good reason. I don’t blame him. There are no second chances after you’ve died for something, at least as far as I know.

“Tell me the activation code again,” Matthew says. The activation code will enable the memory serum weapon, and another button will deploy it instantly. Matthew has made Caleb repeat them both every few minutes since we got here.

“I have no trouble memorizing sequences of numbers!” Caleb says.

“I don’t doubt that. But we don’t know what state of mind you’ll be in when the death serum begins to take its course, and these codes need to be deeply ingrained.”

Caleb flinches at the words “death serum.” I stare at my shoes.

“080712,” Caleb says. “And then I press the green button.”

Right now Cara is spending some time with the people in the control room so she can spike their beverages with peace serum and shut off the lights in the compound while they’re too drunk to notice, just like Nita and Tobias did a few weeks ago. When she does that, we’ll run for the Weapons Lab, unseen by the cameras in the dark.

Sitting across from me on the lab table are the explosives Reggie gave us. They look so ordinary—inside a black box with metal claws on the edges and a remote detonator. The claws will attach the box to the second set of laboratory doors. The first set still hasn’t been repaired since the attack.

“I think that’s it,” Matthew says. “Now all we have to do is wait for a little while.”

“Matthew,” I say. “Do you think you could leave us alone for a bit?”

“Of course.” Matthew smiles. “I’ll come back when it’s time.”

He closes the door behind him. Caleb runs his hands over the clean suit, the explosives, the backpack they go in. He puts them all in a straight line, fixing this corner and that one.

“I keep thinking about when we were young and we played ‘Candor,’” he says. “How I used to sit you down in a chair in the living room and ask you questions? Remember?”

“Yes,” I say. I lean my hips into the lab table. “You used to find the pulse in my wrist and tell me that if I lied, you would be able to tell, because the Candor can always tell when other people are lying. It wasn’t very nice.”

Caleb laughs. “That one time, you confessed to stealing a book from the school library just as Mom came home—”

“And I had to go to the librarian and apologize!” I laugh too. “That librarian was awful. She always called everyone ‘young lady’ or ‘young man.’”

“Oh, she loved me, though. Did you know that when I was a library volunteer and was supposed to be shelving books during my lunch hour, I was really just standing in the aisles and reading? She caught me a few times and never said anything about it.”

“Really?” I feel a twinge in my chest. “I didn’t know that.”

“There was a lot we didn’t know about each other, I guess.” He taps his fingers on the table. “I wish we had been able to be more honest with each other.”

“Me too.”

“And it’s too late now, isn’t it.” He looks up.

“Not for everything.” I pull out a chair from the lab table and sit in it. “Let’s play Candor. I’ll answer a question and then you have to answer a question. Honestly, obviously.”

He looks a little exasperated, but he plays along. “Okay. What did you really do to break those glasses in the kitchen when you claimed that you were taking them out to clean water spots off them?”

I roll my eyes. “That’s the one question you want an honest answer to? Come on, Caleb.”

“Okay, fine.” He clears his throat, and his green eyes fix on mine, serious. “Have you really forgiven me, or are you just saying that you have because I’m about to die?”

I stare at my hands, which rest in my lap. I have been able to be kind and pleasant to him because every time I think of what happened in Erudite headquarters, I immediately push the thought aside. But that can’t be forgiveness—if I had forgiven him, I would be able to think of what happened without that hatred I can feel in my gut, right?

Or maybe forgiveness is just the continual pushing aside of bitter memories, until time dulls the hurt and the anger, and the wrong is forgotten.

For Caleb’s sake, I choose to believe the latter.

“Yes, I have,” I say. I pause. “Or at least, I desperately want to, and I think that might be the same thing.”

He looks relieved. I step aside so he can take my place in the chair. I know what I want to ask him, and have since he volunteered to make this sacrifice.

“What is the biggest reason that you’re doing this?” I say. “The most important one?”

“Don’t ask me that, Beatrice.”

“It’s not a trap,” I say. “It won’t make me un-forgive you. I just need to know.”

Between us are the clean suit, the explosives, and the backpack, arranged in a line on the brushed steel. They are the instruments of his going and not coming back.

“I guess I feel like it’s the only way I can escape the guilt for all the things I’ve done,” he says. “I’ve never wanted anything more than I want to be rid of it.”

His words ache inside me. I was afraid he would say that. I knew he would say that all along. I wish he hadn’t said it.

A voice speaks through the intercom in the corner. “Attention all compound residents. Commence emergency lockdown procedure, effective until five o’clock a.m. I repeat, commence emergency lockdown procedure, effective until five o’clock a.m.”

Caleb and I exchange an alarmed look. Matthew shoves the door open.

“Shit,” he says. And then, louder: “Shit!”

“Emergency lockdown?” I say. “Is that the same as an attack drill?”

“Basically. It means we have to go now, while there’s still chaos in the hallways and before they increase security,” Matthew says.

“Why would they do this?” Caleb says.

“Could be they just want to increase security before releasing the viruses,” Matthew says. “Or it could be that they figured out we’re going to try something—only, if they knew that, they probably would have come to arrest us.”

I look at Caleb. The minutes I had left with him fall away like dead leaves pulled from branches.

I cross the room and retrieve our guns from the counter, but itching at the back of my mind is what Tobias said yesterday—that the Abnegation say you should only let someone sacrifice himself for you if it’s the ultimate way for them to show they love you.

And for Caleb, that’s not what this is.

CHAPTER FORTY-SIX

TOBIAS

MY FEET SLIP on the snowy pavement.

“You didn’t inoculate yourself yesterday,” I say to Peter.

“No, I didn’t,” Peter says.

“Why not?”

“Why should I tell you?”

I run my thumb over the vial and say, “You came with me because you know I have the memory serum, right? If you want me to give it to you, it couldn’t hurt to give me a reason.”

He looks at my pocket again, like he did earlier. He must have seen Christina give it to me. He says, “I’d rather just take it from you.”

“Please.” I lift my eyes up, to watch the snow spilling over the edges of the buildings. It’s dark, but the moon provides just enough light to see by. “You might think you’re pretty good at fighting, but you aren’t good enough to beat me, I promise you.”

Without warning he shoves me, hard, and I slip on the snowy ground and fall. My gun clatters to the ground, half buried in the snow. That’ll teach me to get cocky, I think, and I scramble to my feet. He grabs my collar and yanks me forward so I slide again, only this time I keep my balance and elbow him in the stomach. He kicks me hard in the leg, making it go numb, and grabs the front of my jacket to pull me toward him.

His hand fumbles for my pocket, where the serum is. I try to push him away, but his footing is too sure and my leg is still too numb. With a groan of frustration, I bring my free arm back by my face and slam my elbow into his mouth. Pain spreads through my arm—it hurts to hit someone in the teeth—but it was worth it. He yells, sliding back onto the street, his face clutched in both hands.