Doctor Who, Doctor/Donna, strange things at the back of her mind can't possibly be memories

There is a man.

She supposes that she's seen him before, sometime when she is awake, and for some reason her brain has made him out to be important somehow, because he is in her dreams all the time. And he is not particularly handsome, either, not the kind of handsome she usually finds handsome – too thin, a grin she can only call dorky, wears glasses (sometimes) and sneakers with a pinstripe suit. Who wears sneakers with a pinstripe suit? No one, Donna thinks, but that's what this man wears, every single time he's there in her dreams.

And for some reason, in the dreams, she likes him a lot. He's her best mate and she does everything with him, this man she can't even remember seeing. Maybe he was a salesman once, or one of her friends' many boyfriends. The latter would explain why her subconscious thinks he's so special.

But that's not all, either. That would be enough, if it were just the repeated dreams about the man with the sneakers and the pinstripe suit, but there are the things that come with him, too. Like (for some reason) a blue 1950s police box, and the only reason she knows that's what it is is because she looked it up on the internet. Or the idea that in that blue box she can sail across the stars and through time to places that don't exist. Or (even better) the feelings. Of loss and longing and most alarmingly, like her head is going to explode.

Between that and the fact that when she is awake she has a constant feeling like she's forgotten something and she doesn't know what (though she never leaves her car keys anywhere anymore), and the feeling that her family knows something they aren't telling her, Donna Noble is a bit frustrated.

It probably has to do with aliens. Everything has to do with aliens these days. Aliens this, aliens that, aliens stole the planet – it's like the world's gone mad since she was gone.

And that's the other thing, isn't it? She was gone. She knows she was and people keep telling her she was, too. But where? What was she doing? Traveling, her mother says, I don't know where, you didn't say. But Donna knows she never travels, and yet feels that she did…she must have.

The first time it happens, she's watching a movie with her parents. There's a scene that takes place in Pompeii, and the camera pans out, over the mountain and the buildings below, and it bursts out of her:

"It didn't look like that!"

Two heads swivel around and stare at her, and Donna has no idea why she said that at all, because how would she know? It's not as though she's been to Pompeii.

(Has she? There's a niggling feeling in the back of her mind that has something to do with that man – a doctor, she remembers suddenly, he's a doctor; the doctor? Like it's a title or something – but when she grasps for it, there is nothing. And that's impossible. Aliens and spaceships are one thing, maybe, but time travel…)

"In my dream," she adds, finally. "I must have had a dream – I've just remembered. I do have the funniest dreams sometimes."

And her family seems happy to forget, and they move on.

On Thursday, August 26th, she comes across a blue box in an alleyway, and after blinking at it for several moments, goes over and tugs at the door. She's not sure why, but it doesn't matter, because the door is stuck anyway. "Someone should get rid of this," she says, unaccountably irritated. "It's an eyesore."

"I completely agree with you," says a man behind her, "It's terrible. They should do something about it at once."

"Are you having the mickey at me?" Donna wants to know, half turning around, but the man's already turning away, and all she catches is a brown trenchcoat and red Converse sneakers.

"Nope," he says, voice light and airy and strangely familiar. "Not at all. Just passing through. On my way, then. Thanks, bye!"

There was a peculiar familiarity about that voice, but when she tried to explore it, once again she came up empty.

That night the man of her dreams (not like that, though) had with his pinstripe suit and his sneakers and his glasses a long brown trenchcoat. And the sneakers were red. (Which really just proves her theory, doesn't it? She's making this man out of people she's seen every day.)

When Donna passed by the alleyway, just by coincidence (she swears to herself) the next day, the blue police box is gone. She stands there for a long time, trying to make sense of things, but it's like trying to catch dust with her bare hands; she grabs at where it was, but when she opens her hands to look there's nothing there.

And the man (the doctor) tells her in her dreams, over and over, you can't remember. You musn't. And she thinks that he really doesn't know that much about humans, if he thought that would help, and then wonders why she says 'humans' like he's something else. As if he's even real and not a piece of silly dreams.

This is all not to say she's dissatisfied – she isn't. Her life is ordinary and pleasant, and that's all she's ever asked for, isn't it? No, she is satisfied, and that's what's strange, because sometimes when she sits very, very still she gets the feeling that she shouldn't be satisfied, that this shouldn't be enough. And that's just rubbish.

You can't remember. You musn't.

But Donna's human, and she wants to.

She visits a hypnotist, and he seems puzzled by what she says. "What's a Time Lord?" He asks. Donna shrugs.

"I have no idea."

And she doesn't, she really doesn't (except when she does) and if she only had the answers, all the answers. (She had them once. She knew everything once. All of time and space and)

What is she talking about?

She looks 'Time Lord' up on the internet and only comes up with a bunch of crackpot sites and stupid theories and a lot of babbling that doesn't make any sense to her about a temporal rift in Cardiff. She types up a post about the man with the suit and the coat and the sneakers and hovers the mouse over 'post' for about five minutes, and finally closes the page without clicking.

Like trying to catch dust, and sometimes she's sure she has it (Daleks, what are Daleks? Exterminate, yes, she – doesn't remember, it's only her grandfather's stories) and then it's gone, cast back into shadow.

That's the funny thing about dust, though. You can catch it and hold it, maybe, but you'll never see it in your hands unless the light is just right.