A/N: This chapter was unbelievably hard to write. I'm not really sure why, but I had a harder time connecting with Tobias in this chapter than I did with the previous one. Also, because I'm a health science student and also a touch OCD about my writing, I had to do a bit of research to make sure that the technical aspects (you'll see what I mean later) were accurate (or at least as close to accurate as I could make them, given that I didn't really have time to look into it extensively.)

Thank you all so, so much for your support – I honestly wouldn't have been motivated enough to finish this chapter if it wasn't for all of you! :)

Chapter 52: Tobias

I don't even know what time it is, but I tear myself off the chair in Tris' room and run back to the hotel to find Caleb and Cara. It's probably too early to be waking them up, but I'm so numb I don't even care. There's a part of me that believes if I push myself to run fast enough, I can outrun the truth and tomorrow when we wake up, none of this will be real. Tris will lean out of bed and run her fingers through my hair, telling me that it's getting too long now. She'll steal bits of my breakfast while I'm not looking. She won't be paralysed. She won't.

I sort through my memories and picture her climbing the Ferris wheel, jumping off the train, throwing knives at targets, running along the paths in the Pit. Always alive with movement. Then I try to imagine what it would be like, not to be able to experience those things again, to have that choice stolen from you. I've never had cause to think about it before, but now I realise that there's a big difference between being alive and actually living.

Either by instinct or purely by chance, my feet somehow find their way to the hotel room. I locate Caleb's bed easily and shake him roughly by the shoulders, barely even giving myself a chance to feel guilty about it. "Caleb, wake up! Tris is-" I stumble on the word 'paralysed' and say instead, "She can't move. She can't feel or move anything below her neck."

"What?" His voice is flat as he rubs the sleep from his eyes and I'm reminded that this has been a hard day for him, too. Maybe I should tone down the accusatory edge to my voice a little.

I don't even have to wake Cara – she's already up, her eyes bright and alert. "I'll go get Matthew. We'll meet you back in Tris' room." She pauses on her way out to rouse Christina gently.

Tris doesn't react when I return – she just fixes her gaze on the ceiling without acknowledging our presence and none of us can think of anything to say that wouldn't make the situation worse, so we just hover awkwardly around the room, waiting for Cara. It's not long before she bursts through the door, dragging Matthew behind her. I assume that Cara has explained everything to him on the way, but he looks like he's still stuck halfway between exhaustion and disbelief.

As soon as he's through the door, I ask him, "Why can't she move?" It's hard to mask the anger in my voice, even though I know he's as much to blame as any of us.

Matthew just shrugs his shoulders in defeat and looks at Caleb helplessly. It must be the result of spending too much time surrounded by Erudite minds, but I recognise the expression on Caleb's face – he's studying Tris critically, like he's trying to fit together a puzzle and she's the last piece. "Well are you going to tell us, or am I going to have to re-break your nose?"

Caleb jumps and eyes me nervously. Good, he should be scared.

He doesn't need me to remind him again, pausing only for a second to organise his thoughts. "I've studied the death serum before," he admits. "My theory is that the serum contains two components – one sends you into a simulation-type state and attempts to lull you into sleep, which Tris managed to fight off. The other part is a virus that attacks your sensory and motor nerves – once the muscles that help you breathe stop working, you die. There's a chance that Tris' Divergent genes gave her a degree of resistance to the virus, so they still damaged her system, but nowhere near to the extent that they could have."

Christina stares at Caleb with her mouth open and her expression is so comical that I might have been tempted to laugh, under different circumstances. For a while, no one moves, and the silence drags on until it starts to become uncomfortable. Eventually, Cara folds her arms and nods in agreement. "It does make sense."

Almost at the exact same time, we all turn to look at Tris, who is still acting like nothing has happened. I start to consider the possibility that she's gone into a state of shock - so much has happened to her today, that maybe the only way her brain knows how to cope is to shut itself down and block everything out. Christina takes a few cautious steps forward, and slides herself onto the edge of Tris' bed, careful not to jostle her. "Hey. It's ok, you know. It doesn't matter what happens – we won't love you any less."

I don't think it's the best comment to make, but at least it provokes Tris enough to make her angry. And angry is better than nothing at all. "It matters to me, okay? I can't be Dauntless in a wheelchair."

"Since when was bravery about how you moved?" I counter. Tris opens her mouth to protest, but I don't give her the chance. "Exactly. It isn't. Bravery isn't how fast you can run, or how accurately you can shoot. It's about your strength of character. And last time I checked, throwing yourself into a cloud of death serum vapour to protect the people you love is one of the most courageous things anyone could possibly do, Dauntless or not."

"Besides," Cara adds, "you're no longer bound by the limits of your faction. You're not Dauntless, or Abnegation, or Divergent. You're just Tris. You can be whatever and whoever you want to be."

Tris goes back to scowling at the ceiling, but her response doesn't seem to faze Christina, who has never been the sort of person to avoid difficult questions or situations – she just throws herself into the deep end and deals with the consequences later. It's something that annoys me more often than not but today, I'm thankful for her brashness, because it pushes her to ask Caleb the one question everyone else is too afraid to bring up. "So what's happened to Tris...can you reverse it?"

Caleb takes his time to put together an answer – it's not the sort of question you take lightly. "Theoretically, yes. We know that the serum contains a virus – if we can find something that destroys the virus, the nerve cells will repair themselves."

I'm all too aware that we shouldn't be having this conversation in front of Tris, because although it might be giving her hope, it could all amount to nothing – and she's already had too much false hope in her life. Even so, I can't resist asking Caleb one last thing, though I'm not positive I want to hear the answer. "And do you think you have what it takes to find this 'something'?" It ends up coming out more like a challenge than a question.

If Caleb notices my tone, he doesn't let on. "Jeanine knew David had an inoculation against the death serum, and she didn't like that he chose to withhold it from the faction leaders. She thought it was their right to have access to it, so when he refused her, she started working on an antidote to the serum. I guess that's just how her mind worked - if her pride was hurt, she retaliated with spite. When she died, she'd just finished making the first test batch of the antidotes."

Christina glares at him. I guess she doesn't like to be reminded of the fact that not too long ago, Caleb was working alongside the woman who mind-controlled an entire faction, and nearly destroyed another. In Christina's books, that probably amounts to joint responsibility for Will's death. "And how come you know so much about it?"

Caleb smiles, but his eyes are dark. "Because I was the one who helped her make it."

For the next couple of weeks, Tris refuses to speak to any of us. Matthew gives up trying to persuade her to eat after the first two days and resorts to pumping nutrition through one of the lines in her arms. Even though Caleb is confident that he can replicate the formula for the antidote without Jeanine's notes, I think Tris is too scared to put much faith in it. She'd never admit it, but I know there was a part of her that hoped her parents were still alive somehow, after meeting Amar. The disappointment when she realised she was wrong must have been crushing, so that level of hope isn't something she's likely to subject herself to again.

We take turns watching over her, in case anything goes wrong. I start to get a sense of how Tris felt when I refused to accept her reassurances that my 'damaged' status didn't change who I was, and couldn't change how she felt about me. There's also a part of me that wants to tell her I know how it feels, to explain to her that when Matthew told me my Divergence was just a result of a genetic glitch, I felt like an imposter in my own body. Like I didn't even know who I was anymore, without that part of my identity. But I don't say anything; I don't pretend that being told you're genetically damaged is the same thing as finding out you've lost the ability to control your own body.

I think sometimes, being physically present for someone does more for them than words of comfort. We avoid saying things like 'It's going to be okay' and 'It'll all work out' because really, statements like that are just empty promises – we have no way of knowing if they're actually true. Instead, we just let her grieve in silence without ever straying far, in case she needs us.

So I stay with her, and I wait. And slowly, Tris comes back to us, piece by piece – a smile here, a comment there. She still won't let anyone help her with food, but she starts talking and asking questions – about how our city is rebuilding itself, how my mother is settling into life here, how the Bureau members are recovering after having their memories altered. One day, she asks if I'll take her to the control room with the screens so she can see the progress that Johanna and the other elected leaders are making for herself.

Here's the thing – everyone often has grand ideas of what it means to be brave. But Tris has taught me that bravery isn't always raucous and confronting. It's not always about having the least amount of fears, or fighting someone stronger than you, or being able to wield a gun.

There's also bravery in the small act of waking up each morning, not knowing what lies on the other side of the day. We are all born brave – the difference is whether or not we choose to act on it.

A/N: All right guys, the next chapter will be the last one before the epilogue! I'd love to hear your feedback about the things you liked about this chapter and/or what you thought I could have done better. I appreciate every single one of your reviews and I take them all seriously!

Thank you for sticking by me so far and I hope you enjoyed this chapter :) I'll be working hard to post the final chapter + epilogue within the next few days!