Title- Tempus Immemorialis

Rating- Oh, quite mild. PG I should guess.

Summary- Rose doesn't know quite how old she is anymore, and wishes she could remember. The Doctor knows exactly how old he is, and wishes he could forget.

A/N- My first Doctor Who fic. I'm quite obsessed with DW at the moment, and wanted to give it a try. Don't think there're any spoilers here. I think this can be either ninth or tenth doctor, depending on your preference. I prefer the tenth myself but…

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Rose doesn't know how old she is anymore, and it bothers her. She'd been nineteen when she'd left, but all this mucking about in time…with jumping back and forth through centuries and millennia, she can't be sure at all now. After all, she'd been gone a whole year the first time. According to the normal sense of such things, anyway. So when Rose lies on her bed on TARDIS, staring at the ceiling, unable to sleep after some hair-raising adventure or another, she tries to count up the weeks, months. Had it been years? She's not quite sure.

The Doctor knows exactly how old he is, down to the second, when he cares to think about it that much. He never does. Instead, he measures the time of his life with his experiences; the things he's seen and done, his different incarnations, the deaths of the people he's loved. When he first realizes that he measures time in terms of death, it disturbs him. Even now, sometimes when he's by himself, sprawled over the floor of the control room or alone in some cell on an alien planet, it still does.

When he first tosses out the nine hundred number, Rose knows that she doesn't, can't comprehend it. She doesn't even understand her own aging process anymore, let alone trying to wrap her head around a longevity that stretches over centuries. Slowly, over the time that seems to stretch on forever when she travels with him, watching him saving worlds with haunted eyes or laughing merrily as he introduces her to something new, she realizes that no matter how old she may or may not be, she's never going to have anything on him. That doesn't really bother her, so she supposes that how old she is shouldn't either. And in the end she finds that it doesn't.

When he tells her how old he is, it's as much for the shock value as anything else. He knows that sometimes she forgets how alien to her he is. How very alien. He wishes he had the luxury of forgetfulness. But he doesn't forget, he never forgets, and there are times when the memories come very close to making him feel that death is the only true way to understand time. It's when he starts feeling like that that he grabs Rose's hands and drags her off to somewhere fantastic, just to see her happy, smiling, laughing. Because no matter how old he is, how brightly Gallifrey explodes in front of his eyes whenever he closes them, being with her means that maybe, sometimes, he doesn't have to remember quite so much.

They stop off at Rose's mum's flat just in time for Christmas that year. Jackie is little more inclined than ever to be charitable towards the Doctor, but as long as physical violence is kept to a minimum, Rose is perfectly willing to tolerate some squabbling. Her mum had put a couple of presents for her under the small tree, but a separate one gets pulled out from the wardrobe almost as soon as she's walked in the door and settled into the sofa with a cup of tea. Jackie hands her the gift, and the Doctor leans in, curious.

"What's this, then?" Rose asks, hefting the package gently. "My birthday was ages ago, Mum, and this isn't Christmas wrapping."

"I know love, but you weren't here for your birthday and you haven't been home since." Here, Jackie glares at the Doctor, who is eyeing Rose with interest and her mother with trepidation. "My little girl, out there getting all that much older. The least I can do is have a little prezzie waiting for you here at home. Go on now, open it up."

It's not until after they leave, full of turkey and Christmas spirit, and are back on the TARDIS headed towards stars unknown that the Doctor brings it up. "I sorry, you know, that we never celebrated your birthday. We can, if you want, time machine and all that. We could go back to any one you like. Can't have you meeting yourself, of course, but a bit of ice cream or something wouldn't go amiss, I don't think."

Rose turns to look him squarely in the face. She isn't blind, and she knows that the Doctor doesn't like to think about her aging any more than he likes to consider what that very aging means for her in the long run. She knows by now that he remembers exactly how old she is, a lot more carefully than she ever could. And she knows, even if she doesn't fully understand, how hard it is for him to even offer to commemorate the passing of her time, since to him it just means that he's one step closer to losing her.

No, Rose isn't blind and while she is sometimes foolish or tactless, one thing she does know how to do is learn. And she's learned by now that it doesn't matter how long she's been gone, or how many years her body has aged in that time; what matters is that there is a now, and that the present is more important then a thousand celebrated and counted birthdays.

So she smiles at him, as brightly as she can, trying to convey in a single look how much his caring means to her, and says, "Don't be silly, there're so many better places to be going off to. Not that I would mind a bit of ice cream. Or some chips. Maybe both?"

And when the Doctor look at her now, young and uncaring of the years that he knows are spinning by, he knows as surely as anything that time might not have to be measured in death. That maybe, every now and again, it can be measured by life, instead. And it's armed with that knowledge that he reaches over suddenly and manipulates the TARDIS controls until they're spinning faster and faster, out into time and space, both of them laughing until finally the movement stops and they've landed somewhere absolutely new. He grins back at her widely, and holds the door open, inviting her to step out into the unknown. But before she quite gets out the door, he grabs her hand in his, steps up to stand next to her, and they walk out into foreign lands together.