He thinks he might be falling for her.

And, well, that conclusion comes as a surprise to no one more than him. He's not supposed to feel that sort of thing. He hasn't felt anything remotely like this for a long time. Not this.

He isn't too sure when it started, or how far through the process he is. He isn't sure if he's ever going to stop. And he certainly isn't sure what to do about it.

All he knows is this:

She has this hand that fits perfectly in his.

She has this brain that works things out – mystery after mystery; even him.

She has this face that expresses her every thought and feeling, and it touches him to his inner soul; the way her eyes light up, the way her mouth smiles so wide – and then the opposite, the expressions of fear and hurt and sometimes tears on her cheeks, oh, that's the worst, that is, it makes him feel sick.

She is beautiful; he hadn't lied to her, except that he had, just a little, because she is not beauty with a qualifier, she is not beautiful considering she is human, she is just…wonderful. Full stop.

And, okay, so maybe he's smitten. But despite the fact that a Time Lord shouldn't be feeling like this, he had no chance, really, when you think about it. After all, she is the person who talks of him seeing days that are dead and gone, a hundred thousand sunsets ago – and now, oh blimey, since she promised him with those eyes and that smile and the words better with two, he bloody well hopes she means to see those days with him.

He can't get too dependent on her, he knows that. She will flutter through his life so quickly. She is human, and humans aren't built to stay. However much they might want to.

(He shudders when he thinks like that, thinks of her not being here. For even when she's glaring at him across the console when he's rude, or spilling her can of Coca Cola over the grating and being forgiven by the TARDIS as quick as anything – the Old Girl's getting soft – or arguing with him over the choice of location or morality or tea with her Mum…it all means so much, and to have that taken away, well, he can't dwell on that too much or else he'd never stop)

The thing is, she doesn't even realise. She talks about Mickey, her sort-of boyfriend who she sort-of ended things with back in Cardiff. She befriends all these Adams and Jacks and she doesn't really venture into the romantic territory with any of them, thank the universe, but knowing that there is a consistent threat of potential there, well, it eats away at him quite nicely.

He could tell her, he supposes. Could just blurt it out, in the way he quite emphatically told her that he does dance, thank you, in the way he said, no Jack, you cannot go near her bedroom, ever.

But he's still caught up in this sense of self-punishment, this trap he has placed himself in of not deserving and being too damaged and –

What if he breaks her heart?

That's his biggest fear, that – that he'll hurt her, and that'll be the reason she leaves. Because he can protect her the best he can, just like she protects him right back – they're a good team, they really are – but at the end of the day, he's not so certain he can protect her from himself. He has destroyed so much. He has lost nearly everything.

Destroying or losing her – or both – would be the final straw. And admitting things like emotions and thoughts and wishes of happily-ever-afters that can't happen, that's just inviting trouble right in, that is.

He hopes that she works it out, one day, though. If he can't tell her, then he hopes she just works it out, like she works out everything else. And perhaps, if she knows, and if she feels the same way – maybe then she'll break down his defences a bit more. Maybe then he'll have the courage to do what he's wanted to do for so, so long, and kiss her.

Maybe. Maybe.