Christina and I stare at each other. "He's a liar. You can't believe anything he says," my voice is cold and I can't help myself. "He manipulates people and hurts them for his own end. And he's very good at making people believe in him."

"This is not about you, Tobias."

Tobias. She called me by my name. Did Tris tell her? Why would she do that?

"Oh, really? And how do you know it's not about me? Just because Tris told you my real name doesn't mean you know anything about me."

Christina looks at me strangely. "You told me," she snorts. "Along with everyone in Candor and half of Dauntless. Remember?"

Oh. The truth serum. Right. I am mumbling something about how I was trying to forget that when Christina leans in, close to my face. I try not to recoil at the proximity.

"It's not about you, Tobias," she repeats. "And you don't deserve her if you don't understand the courage it took to do this without telling you, even in a simulation."

"Well, you'll have to forgive me if it seems more like a betrayal than bravery."

We glare at each other for a moment, and then Christina makes a sound of disgust in her throat and turns away. "I'm going to watch now, to see if there's anything I can do to help Tris," she says pointedly.

I look away from her, over at Cara and Leo, watching them for a few minutes. They lean their heads together, murmuring and pointing at the screen. Cara looks down at Caleb's journal every now and then. Across the room, Darius is scrolling through different camera views. He looks intent and alert, but not especially worried.

I sigh and turn back to the big screen, hesitating slightly before giving Christina's shoulder a squeeze, a tacit apology. She pats my hand, never taking her eyes off the picture.

"The Amity leader…" she notes.

"Johanna," I supply.

"She just broke with her faction because she said she couldn't stand by as people lost their lives. Lots of brain activity when it happened. Hey! Check that out! Cara, you just showed up!"

"Yes, I rather thought I might," she says, without taking her eyes off the screen in front of her. "What am I doing?"

"You're telling us our plan is flawed, of course. But you're helping us, anyway."

"And how am I acting toward Tris?"

"Oh, a little frosty, but you're talking to her, and you're helping her. Now you're saying something about the data network, where Erudite can access computers from all the other factions."

Cara turns to look at us, her eyebrows shooting up. "Really? I said that? Now, how would Tris know about that?"

"Probably from me," I say. "I worked in the Control Room at Dauntless, and I'm good with computers. I told her a little about how it works and how I was able to find the Erudite attack plans on the Dauntless computers.'

Cara looks at me, shock and respect mingling on her face. "Well, you are full of surprises, aren't you, Four?"

"Leo!" Darius says urgently, staring at the computer screen. "We got trouble. Sam's in trouble."

Leo and I move to Darius's side. One of the cameras shows a group of about eight factionless and Dauntless, crouching behind a corner down the hall from Sam, shooting at him. He's holding his own, but probably not for long. I'm not sure, but I think one of the Dauntless might be Tori.

Leo nods grimly: "Let's go," he says to Darius. He turns to Cara, who has glided silently to his side, and puts his hands on her shoulders. "I think you may be the bravest Erudite I've ever met," he says quietly.

"And you may be the smartest Dauntless I've ever met."

Leo suddenly pulls her into his arms and kisses her soundly on the mouth. I expect her to swat him away and scold him, but she doesn't. She wraps her arms around his neck and presses her body into his, kissing him back even harder.

"Leo…" Darius says urgently.

Leo pulls back from Cara and they look at each other for a moment longer. She nods gently and strokes his face. He lets her go, turning away, and I clear my throat, moving to follow him.

"Where are you going?" Leo says, looking at me.

"Coming with you, of course."

He grips my shoulder with one hand. "No, Four. You have to stay here. I think Cara has figured it out, and you're the key to the whole thing. You can't leave now if you want Tris to survive this – and we may need her if we're all going to survive. We'll be OK."

"I'll go," Christina says, holding her hand out for my gun. Leo nods and follows Darius out the door.

Christina's gaze never wavers as she waits for the gun. I give her all three. As she starts to run after Leo and Darius, I call after her.

"Christina," she looks back over her shoulder at me. "You're a good friend. To both of us."

She grins at me. "Aw, who knew you could be such a softie, Four? Don't worry. I'll be back – you can't get rid of me that easily." And then she's gone.