The logical puzzle: In a fight between two perfect equals, how can one win?

The answer: One can’t.

She pushes herself to her feet and wipes the blood from her lip.

Therefore: we must not be perfectly equal. So what is different about us?

She walks toward me again, but I need more time to think, so for every step she takes forward, I take back. The room sways, and then twists, and I lurch to the side, brushing my fingertips on the ground to steady myself.

What is different about us? We have the same mass, skill level, patterns of thinking . . .

I see the door over her shoulder, and I realize: We have different goals. I have to get through that door. She has to protect it. But even in a simulation, there is no way she is as desperate as I am.

I sprint toward the edge of the circle, where there is a table. A moment ago, it was empty, but I know the rules of simulations and how to control them. A gun appears on it as soon as I think it.

I slam into the table, the spots crowding my view of it. I don’t even feel pain when I collide with it. I feel my heartbeat in my face, like my heart has detached from its moorings in my chest and begun to migrate to my brain.

Across the room, a gun appears on the ground before my double. We both reach for our weapons.

I feel the weight of the gun, and its smoothness, and I forget about her; I forget about the poison; I forget about everything.

My throat constricts, and I feel like there is a hand around it, tightening. My head throbs from the sudden loss of air, and I feel my heartbeat everywhere, everywhere.

Across the room, it’s no longer my double who stands between me and my goal; it’s Will. No, no. It can’t be Will. I force myself to breathe in. The poison is cutting off oxygen to my brain. He is just a hallucination within a simulation. I exhale in a sob.

For a moment I see my double again, holding the gun but visibly shuddering, the weapon as far out from her body as she can possibly hold it. She is as weak as I am. No, not as weak, because she is not going blind and losing air, but almost as weak, almost.

Then Will is back, his eyes simulation-dead, his hair a yellow halo around his head. Brick buildings loom from each side, but behind him is the door, the door that separates me from my father and brother.

No, no, it is the door that separates me from Jeanine and my goal.

I have to get through that door. I have to.

I lift the gun, though it hurts my shoulder to do it, and wrap one hand around the other to steady it.

“I . . .” I choke, and tears smear my cheeks, run into my mouth. I taste salt. “I’m sorry.”

And I do the one thing my double is unable to do, because she is not desperate enough:

I fire.

CHAPTER FORTY-FIVE

I DON’T SEE him die again.

I close my eyes at the moment the trigger presses back, and when I open them, it is the other Tris who lies on the ground between the dark patches in my vision; it is me.

I drop the gun and sprint toward the door, almost tripping over her. I throw my body against the door, twist the handle, and fall through. My hands numb, I press it closed behind me, and shake them to regain feeling.

The next room is twice as big as the first one, and it, too, is blue-lit, but paler. A large table stands in the middle, and taped to the walls are photographs, diagrams, and lists.

I take deep breaths, and my vision begins to clear, my heart rate returning to normal. Among the photographs on the walls, I recognize my own face, and Tobias’s, and Marcus’s, and Uriah’s. A long list of what appear to be chemicals is posted on the wall beside our pictures. Each one is crossed out with red marker. This must be where Jeanine develops the simulation serums.

I hear voices somewhere ahead of me, and scold myself. What are you doing? Hurry!

“My brother’s name,” I hear. “I want to hear you say it.”

Tori’s voice.

How did she get through that simulation? Is she Divergent too?

“I didn’t kill him.” Jeanine’s voice.

“Do you think that exonerates you? Do you think that means you don’t deserve to die?”

Tori is not screaming, but wailing, the whole of her grief escaping through her mouth. I start toward the door. Too quickly, though, because my hip slams into the corner of the table in the middle of the room, and I have to stop, wincing.

“The reasons for my actions are beyond your understanding,” Jeanine says. “I was willing to make a sacrifice for the greater good, something you have never understood, not even when we were classmates!”

I limp toward the door, which is a pane of frosted glass. It slides back to admit me, and I see Jeanine, pressed against a wall, with Tori standing a few feet away, her gun high.

Behind them is a glass table with a silver box on it—a computer—and a keyboard. The entire far wall is covered with a computer screen.

Jeanine stares at me, but Tori doesn’t move an inch; doesn’t seem to hear me. Her face is red and tear-streaked, her hand shaking.

I have no confidence that I can find the video file on my own. If Jeanine is here, I can get her to find it for me, but if she’s dead . . .

“No!” I scream. “Tori, don’t!”

But her finger is already over the trigger. I launch myself at her as hard as I can, my arms slamming into her side. The gun goes off, and I hear a scream.

My head hits the tile. I ignore the stars in my eyes and throw myself across Tori. I shove the gun forward and it slides away from us.

Why didn’t you grab it, you idiot?!

Tori’s fist connects with the side of my throat. I choke, and she uses the opportunity to throw me off, to crawl toward the gun.

Jeanine is slumped against the wall, blood soaking her leg. Leg! I remember, and punch Tori hard near the bullet wound in her thigh. She yells, and I find my feet.

I step toward the fallen weapon, but Tori is too quick. She wraps her arms around my legs and pulls them out from under me. My knees slam into the ground, but I am still above her; I punch down, at her rib cage.

She groans, but it doesn’t stop her; as I drag myself toward the gun, she sinks her teeth into my hand. It is a different pain than any blow I’ve ever received, different even from a bullet wound. I scream louder than I thought possible, tears blurring my vision.

I have not come this far to let Tori shoot Jeanine before I’ve gotten what I need.

I yank my hand from between her teeth, my vision going black at the edges, and with a lurch, smack my hand around the handle of the gun. I twist, and point it at Tori.

My hand. My hand is covered in blood, and so is Tori’s chin. I hide my hand from view so that it’s easier to ignore the pain and get up, still pointing the gun at her.

“I didn’t take you for a traitor, Tris,” she says, and it sounds like a snarl, not a sound any human can make.

“I’m not,” I say. I blink the tears down my cheeks so that I can see her better. “I can’t explain it right now, but . . . all I’m asking is for you to trust me, please. There’s something important, something only she knows the location of—”

“That’s right!” says Jeanine. “It is on that computer, Beatrice, and only I can locate it. If you don’t help me survive this, it will die with me.”

“She is a liar,” says Tori. “A liar, and if you believe her, you are both an idiot and a traitor, Tris!”

“I do believe her,” I say. “I believe her because it makes perfect sense! The most sensitive information that exists and it’s hidden on that computer, Tori!” I take a deep breath, and lower my voice. “Please listen to me. I hate her as much as you do. I have no reason to defend her. I’m telling you the truth. This is important.”

Tori is silent. I think, for a moment, that I’ve won, that I’ve persuaded her. But then she says, “Nothing is more important than her death.”

“If that’s what you insist upon believing,” I say, “I can’t help you. But I’m also not going to let you kill her.”

Tori pushes herself to her knees, and wipes my blood from her chin. She looks up into my eyes.

“I am a Dauntless leader,” she says. “You don’t get to decide what I do.”

And before I can think—

Before I can even think about firing the gun I’m holding—

She draws a long knife from the side of her boot, lunges, and stabs Jeanine in the stomach.

I yell. Jeanine releases a horrible sound—a gurgling, screaming, dying sound. I see Tori’s gritted teeth, I hear her murmur her brother’s name—“George Wu”—and then I watch the knife go in again.

And Jeanine’s eyes turn into glass.

CHAPTER FORTY-SIX

TORI STANDS, A wild look in her eyes, and turns toward me.

I feel numb.

All the risks I took to get here—conspiring with Marcus, asking the Erudite for help, crawling across a ladder three stories up, shooting myself in a simulation—and all the sacrifices I made—my relationship with Tobias, Fernando’s life, my standing among the Dauntless—were for nothing.

Nothing.

A moment later, the glass door opens again. Tobias and Uriah storm in as if to fight a battle—Uriah coughing, probably from the poison—but the battle is done. Jeanine is dead, Tori is triumphant, and I am a Dauntless traitor.

Tobias stops in the middle of a step, almost stumbling over his feet, when he sees me. His eyes open wider.

“She is a traitor,” says Tori. “She just almost shot me to defend Jeanine.”

“What?” says Uriah. “Tris, what’s going on? Is she right? Why are you even here?”

But I look only at Tobias. A sliver of hope pierces me, strangely painful, when combined with the guilt I feel for how I deceived him. Tobias is stubborn and proud, but he is mine—maybe he will listen, maybe there’s a chance that all I did was not in vain—

“You know why I’m here,” I say quietly. “Don’t you?”

I hold out Tori’s gun. He walks forward, a little unsteady on his feet, and takes it.

“We found Marcus in the next room, caught in a simulation,” Tobias says. “You came up here with him.”

“Yes, I did,” I say, blood from Tori’s bite trickling down my arm.

“I trusted you,” he says, his body shaking with rage. “I trusted you and you abandoned me to work with him?”

“No.” I shake my head. “He told me something, and everything my brother said, everything Jeanine said while I was in Erudite headquarters, fit perfectly with what he told me. And I wanted—I needed to know the truth.”

“The truth.” He snorts. “You think you learned the truth from a liar, a traitor, and a sociopath?”

“The truth?” says Tori. “What are you talking about?”

Tobias and I stare at each other. His blue eyes, usually so thoughtful, are now hard and critical, like they are peeling back layer after layer of me and searching each one.

“I think,” I say. I have to pause and take a breath, because I have not convinced him; I have failed, and this is probably the last thing they will let me say before they arrest me.

“I think that you are the liar!” I say, my voice quaking. “You tell me you love me, you trust me, you think I’m more perceptive than the average person. And the first second that belief in my perceptiveness, that trust, that love is put to the test, it all falls apart.” I am crying now, but I am not ashamed of the tears shining on my cheeks or the thickness of my voice. “So you must have lied when you told me all those things . . . you must have, because I can’t believe your love is really that feeble.”

I step closer to him, so that there are only inches between us, and none of the others can hear me.

“I am still the person who would have died rather than kill you,” I say, remembering the attack simulation and the feel of his heartbeat under my hand. “I am exactly who you think I am. And right now, I’m telling you that I know . . . I know this information will change everything. Everything we have done, and everything we are about to do.”

I stare at him like I can communicate the truth with my eyes, but that is impossible. He looks away, and I’m not sure he even heard what I said.

“Enough of this,” says Tori. “Take her downstairs. She will be tried along with all the other war criminals.”

Tobias doesn’t move. Uriah takes my arm and leads me away from him, through the laboratory, through the room of light, through the blue hallway. Therese of the factionless joins us there, eyeing me curiously.

Once we’re in the stairwell, I feel something nudge my side. When I look back, I see a wad of gauze in Uriah’s hand. I take it, trying to give him a grateful smile and failing.

As we descend the stairs, I wrap the gauze tightly around my hand, sidestepping bodies without looking at their faces. Uriah takes my elbow to keep me from falling. The gauze wrapping doesn’t help with the pain of the bite, but it makes me feel a little better, and so does the fact that Uriah, at least, doesn’t seem to hate me.

For the first time the Dauntless’s disregard for age does not seem like an opportunity. It seems like the thing that will condemn me. They will not say, But she’s young; she must have been confused. They will say, She is an adult, and she made her choice.

Of course, I agree with them. I did make my choice. I chose my mother and father, and what they fought for.

Walking down the stairs is easier than going up. We reach the fifth level before I realize that we’re going down to the lobby.

“Give me your gun, Uriah,” says Therese. “Someone needs to be able to shoot potential belligerents, and you can’t do it if you’re keeping her from falling down the stairs.”

Uriah surrenders his gun without question. I frown—Therese already has a gun, so why did it matter for him to give his? But I don’t ask. I am in enough trouble as it is.

We reach the bottom floor and walk past a large meeting room full of people dressed in black and white. I pause for a moment to watch them. Some of them are huddled in small groups, leaning on one another, tears streaking their faces. Others are alone, leaning against walls or sitting in corners, their eyes hollow or staring at something that is far away.