"How long have you been doing this?" Donna asks the scrawny legs that she presumes are attached to a scrawny alien half-hidden beneath the grated floor.

The legs don't reply, but from somewhere beneath the console there's an irritated groan. "Have a little patience, Donna, it's only been half an hour and you only got out of the shower twenty minutes ago. It won't be long."

And then there's a muter containing the words "sleep" and "eight hours a day" and "waste of time", so Donna takes care to step loudly on the grate above the source of muttering as she makes her way to the jump seat.

"I meant this," she clarifies, with an expansive gesture around the room that will surely go unnoticed. "Traveling and running and freeing Oods and all that. How long?"

"Oh." The bleeping noise she's come to associate with the sonic screwdriver stops for a moment, and then he says: "A while."

Donna rolls her eyes. "And when you say 'a while', you mean…?"

"A few… hundred… years," he says innocently, as though a few hundred years is a perfectly normal period of time to be doing any one thing.

"A few hundred years?" she repeats. "A few hundred years?"

There are several metallic clangs, three bleeps, one zap and one long string of syllables the TARDIS fails to translate, and then the scrawny alien in question heaves himself out from the depths of the console floor.

"Well, a few hundred, give or take," he concedes. Then he shoves one finger in his mouth, no doubt to nurse whatever minor injury he's given himself this time.

Donna barely registers this; she's far too busy staring at him incredulously.

"Seriously?"

He nods.

Donna's brow crinkles in suspicion. "How old are you?"

"Nine hundred," he manages to say around the finger in his mouth. "…Ish."

Absolutely not, Donna thinks instantly. There is absolutely no way the scrawny alien man-child sitting cross-legged on the floor, sucking at some burn or cut on his index finger is nine hundred.

Is there?

"Nine hundred," she repeats, with the faint hope that repeating it might grant it some measure of credibility.

"Ish," he clarifies, and pulls his finger out of his mouth.

Donna stares. She looks him up and down, scrutinizing, noting the surplus of hair and its absence of gray, the relative lack of wrinkles and the apparent metabolism of a fourteen-year-old.

"Oh, you are kidding me," she mutters, mostly to herself, then folds one arm across her chest. "Well that's just not fair."

The Doctor tilts his head to the side and frowns in thought. "I think… that may be the closest you've ever come to complimenting my physical appearance."

Donna snorts, but can't quite restrain a grin in return. "Yeah, well, don't get used to it." She gives him one last once-over, a tiny portion of her still half-expecting him to morph into Gandalf now that the secret's out. "Just – I mean – nine hundred?"

Even as she says it, Donna realizes it is probably quite rude to repeat someone's age so many times in a single conversation. But really, she figures, it's just as rude to go around looking like that when you're a bloody millennium old, so they're even.

He raises his eyebrows -- thankfully looking more amused than insulted – and springs to his feet to take a seat next to her. "Repeating it incredulously isn't making me any younger!" he tells her, and Donna gets the distinct impression that he's laughing at her. The bastard.

"Besides," he continues, "I doubt you'd want to travel me if I looked my age." He seems to consider the possibility for a second and scratches his jaw. "Or that I'd be doing much traveling at all, really. Hard to, when you're that size. Wouldn't be able to reach the console, for one."

Donna stares at him and surmises, not for the first time, that he is absolutely certifiably mad.

"So if this is what you look like when you're nine hundred, were you like an infant when you were my age?"

The Doctor looks at her and laughs outright, this time. "That's not really how it works, Donna."

"Right," she says, as though it makes any more sense to her now. "That's probably a good thing. Parenting would be rough." She considers this and wrinkles her nose. "The terrible two-hundreds."

Beside her, he snickers and shakes his head; Donna watches him and wonders why it is she gets along with a ridiculously ancient and immature alien better than any human she's ever met. Life is a strange thing, she's learning very quickly.

Certain that if she doesn't latch on to this topic of conversation while she still can, he'll quickly revert back to cultivating his enigmatic persona, she decides to be blunt: "So are there any other weird alien Time Lord-y things I should know about? I mean, all right, you don't age properly and you've got your Vulcan Mind-Meld thing, but –"

"Vulcan Mind-Meld thing?" he interrupts. He looks both indignant and appalled. "I do not 'have' a 'Vulcan Mind-Meld thing'. "

"Time Lord Mind-Meld thing, then," she amends, waving a hand impatiently. "Anyway, is that it? You don't – I don't know – bleed green or something, do you?"

The Doctor raises one eyebrow.

Donna lifts her head defiantly. "Oi! Don't look at me like that, Spaceman, how am I supposed to know? If you're gonna start shooting spores or something I'd better be prepared!"

For a second the Doctor merely stares at her, apparently at a complete loss as to how to respond. Then he says, "There will be no shooting of spores, Donna, I assure you." He shrugs. "Two hearts, though."

"Really?"

Instinctively, automatically, she reaches a hand out and presses it to his chest. The light double thump beneath her palm is different and fascinating and bizarre.

Two hearts, she thinks. Well, she's seen weirder. At least he hasn't got his brain in his hands.

She raises her eyebrows and lowers her hand. "God, it's a bloody drumline in there."

He grins and props his feet up on the console. "Better than a solo," he jokes, and she elbows him in the ribs.

"Is that it, then? I mean, you haven't got four lungs or eight stomachs or something, have you? Oh! Have you got an appendix? Mine burst when I was sixteen, I nearly died, what sort of rubbish organ is that?"

"I -- …no, no appendix, no." His eyes narrow and his forehead crinkles as he studies her. "You really think of me as alien, don't you?"

"Yes," Donna says reflexively, and then has a horrible sensation that she has just botched things up entirely. Perhaps not asking specific questions about physiology is somewhere in the Traveling with Time Lords handbook that she has neglected to read. "…Does that bother you? I mean, you are."

"Oh, no!" he assures her at once, and she relaxes. He scratches the back of his neck and mulls over the question. "Actually, it's sort of nice. Martha and Rose, they… forgot, sometimes, I think."

It's Donna's turn to snicker. "Yeah, well."

Not entirely to her surprise, the Doctor doesn't seem to follow. "'Yeah, well,' what?"

"Yeah, well, I'd probably try and think of you as human, too, if I had any desire to shag you."

The Doctor gapes at her, and Donna – who counts any instance of rendering him speechless as a sound victory for her, on behalf of humanity itself – leaps up and grins, hands on her hips.

"Well then!" she exclaims, and the Doctor finally manages to shut his mouth. "Onwards?"