December 31st, 2009, 5:13 PM. NORTH-EAST SITTING ROOM, THE TYLER MANSION.

It is a dark and stormy night.

"Rose," the Doctor says, leaning over the back of her chair: "How would you like to go blow up a mad scientist's fiendishly clever but thoroughly evil anti-aging device?"

Rose sets down her novel: Agatha Christie, The Green Glass Zeppelin. She asks, "How evil, then?"

The Doctor grins that gorgeous thousand-watt grin of his and says, "Very very evil! It's going to turn him into a big scorpion-y sort of monster bloke, and then he'll try to eat people. A real disaster."

"That's progress for you," Rose remarks, and uses the little paper tag from her teabag to mark her place. "Right then, who's doing it and how do we get there and how soon should I be ready?"

"Professor Lazarus," The Doctor says precisely, and holds up two lovely cream-and-gold invitations. "New Year's Party. Tonight."

Rose beams. "I'll wear the red dress."

9:45 PM. A BROOM CLOSET, LAZARUS LABS.

"I thought you said you had it all sorted! 'Stand back,' you said! 'It'll just be a jiffy,' you said!"

"Rose, is this really the time?" the Doctor asks. His voice is a hoarse Northern drawl, and his hands are massive and bony around her waist.

"Considering we're hiding in a cupboard from a big scorpion monster and you're--you again," Rose hisses, "I can't think of a better time!"

"Rose, please," the Doctor says, and his blue eyes are so sad and grave in the darkness, his daft awkward face so dear and familiar, "we'll get it sorted."

She relaxes, fractionally, in his arms. He's already lost his tuxedo jacket, and his shirt is tight across his chest and bunched strangely around his elbows.

"Are you going to stay like this?" she asks, her voice small and a bit squashy around the edges.

"D'you want me to?" the Doctor asks.

A long, tense moment.

"...I just want to know what's going on."

"I'm regressing. My body's de-aging like Lazarus's. Only I'm still half Time Lord, me, so it's skipping back though my regenerations as well."

"Is it permanent?"

"Not if I can help it."

"Are you going to forget me?"

"No. Never."

"Really?"

"The regression's only physical, looks like. Though my eighth had some rough patches, brain-wise, so-- maybe. For a bit."

"Only you could say 'never' and mean 'maybe'," Rose says.

"You love it," the Doctor asserts, grinning, but he's just a little uncertain.

"I love it," she says, and kisses him, like she's always wished she'd kissed her first Doctor. But against her mouth she can already feel him changing again.

"Doctor?" she asks.

"Hello," the pretty, noble-looking man says in a pretty, noble-sounding voice. "I believe that I should lie down for a while."

He faints.

"Bollocks," Rose says.

10:40 PM. THE SAME BROOM CLOSET.

The Doctor doesn't so much as twitch until he changes again, this time into a portly, avuncular sort of man with ferocious eyebrows and frizzy hair. Rose can't help but feel a little cheated.

"You alright there, Doctor?"

"Yes, I should be," the Doctor murmurs in a surprisingly sweet, lilting voice.

"So what was that?"

"What was what?"

"The bit with the fainting. And then flickering in and out of existence."

"Ah, well, that's Eight for you, he's very quantum," the Doctor says cryptically, and clambers to his feet. If the tux had fitted his Northern self badly, it looks even more terrible on this body, which seems to be broader across the shoulders, wider around the waist, and much shorter along the legs. Rose helps him roll his trouser cuffs.

"That should patch it," the Doctor says, and sighs. "We're going to have a rough night, clotheswise. I've been some very different men."

"What are we going to do, Doctor?"

The Doctor cracks the closet door open and peers out cautiously.

"Lose the police, for one," he says, "and lose Professor Lazarus, for two. I don't fancy explaining to your father how I got you arrested for murder and devoured by your victim on the same night."

They set off, arm in arm. It's surprisingly comfortable: this Doctor has a steady, friendly presence, and a quick bouncing stride.

"So what's with the accent, then?" Rose asks after awhile. "Do lots of planets have a Scotland, too?"

"It's complicated," the Doctor hedges.

"So dumb it down for me, smarty-pants."

"My different incarnations picked up quite a few, oh, endemic mannerisms, as it were. Think of it as a kind of stride: I could--" and here he puts on his regular accent, "--walk the walk, but it just doesn't really fit."

She laughs, and he grins and continues in the lilting burr of this body: "One could move or talk or think however one likes, if one was thinking about it. You could skip everywhere, if you fancied. But in the end, it's easiest to do what comes naturally, and that generally involves whatever one was doing just after regeneration."

"And what you were doing just after this regeneration was waddling along being Scottish."

"Well. More or less. There was this big--"

"What was your, what, your Ninth self doing, then?"

"Pardon?"

"With his-- your accent. What happened? Where were you?"

"Soccer match. New Manchester United."

"You regenerated during a soccer match in Manchester," she repeats flatly.

"New Manchester," the Doctor corrects primly.

"New Manchester," she repeats, and laughs.

The Doctor raises his eyebrows reprovingly: "A life lesson for you, my dear girl: when a man dubbed 'Big Henry Headsmasher' tells you to get out of the way or he'll smash your head in..."

"Get out of the way?"

"I see you've already learned this one," the Doctor says, and taps her on the nose with his finger. She laughs again, startled, and he smiles that same slow sad-happy smile as, she's learning, he's always smiled.

10:52 PM. A HALLWAY.

"Did you know, this body of mine looked almost identical to the Commander of the Guard, back on Gallifrey?"

"No, Doctor, I didn't. Where are we, anyway?"

"Maxil, his name was. Commander Maxil. Nasty character, always poncing around in armor and tight red trousers. Always very keen to have me executed. He shot me once, I don't mind telling you, and he didn't even bother to look sorry about it."

"The nerve of some people!" Rose teases.

"Precisely," the Doctor agrees. "Shooting me is a grave and tragic occasion, and the stuffy twit just hauls off and goes zap! Not even a sneer! Well, I trotted right back to Gallifrey, soon as I got myself sorted, and I went and framed him for-- well, it doesn't matter what I framed him for, but I good and framed him for it. Oooh, was he ever mad."

"What did he do?"

"Ah. Well. He shot me for it next time I was summoned to the Capitol. Apparently I framed him a little early, vis-a-vis our relative time lines."

Rose grins. "Revenge, young Doctor," she intones in her best Time Lord voice, "is a dish best served yesterday."

The Doctor cackles. "Too true! And the best part was that by the time anyone thought to check, Maxil himself had regenerated, and so I made off with his salary as well. I bought ever so many hideous trousers with it. Ghastly, one and all."

"You would never look hideous," Rose says loyally, but ruins the effect by snickering right afterwards.

"Oh, well, I was magnificent," the Doctor grins, wagging a finger at her, "but the trousers were total stinkers."

"You were a bit of a bitch, this incarnation."

"My dear Rose, I'm a bit of a bitch in every incarnation."

11:15 PM. A DEAD END.

"I told you I should have brought my gun! Why did I let you talk me out of bringing my bloody gun!?"

"And I told you, I don't like guns!"

"Okay, A, it's a stun gun, Doctor, and B, I wasn't asking you to use it."

Lazarus makes a lazy feint towards them. Rose keeps her hands raised and her balance centered over her heels, but she's really not sure what three years of hand-to-hand are going to accomplish against something built like a drafthorse and covered in spines.

"Do you have the door open yet, Doctor?" she calls over her shoulder.

"I'm working on it, Rose," the Doctor snaps, all icy impatience and snobby accent, and she has never wanted to smack him more. Clearly all her nightmares have decided to come true at once and she's turning into her mum.

"I really think you should get that door open, Doctor," she calls.

"I really think you should--" the Doctor is saying, but Lazarus seizes on the moment and lunges for her like a twisted, fleshy freight train.

"Doctor!" she shrieks.

The Doctor spins her behind him, wielding a length of lead pipe in his hand like a club, and smacks the monster square across the face. It goes skidding backwards down the hallway, screaming, and the Doctor pulls her through the open door. They re-lock it, hurriedly, and slump together against the wall.

"Nice aim," Rose says.

"Good arms. I rather enjoyed being this me," the Doctor says, and smiles.

"Oh my god," Rose laughs, taken aback, "You have terrible teeth. I thought this you was posh--"

"Teeth are hard!" the Doctor protests, his voice going amusingly high and indignant. "I'd like to see you worry about your teeth when you're busy regenerating all your organs in the right places."

"I'm sorry, I'm sorry," Rose says. She squeezes his hand. "I like your hair," she offers. "That last you looked like a pig in a perm."

"Oh, you think that was bad. Just you wait until Four!" the Doctor warns. "Then you're going to see some teeth and hair."

Professor Lazarus chooses that moment to ram himself into the door. It dents visibly, and Rose, startled, clutches at the Doctor and screams.

"Brave heart, Rose. Come on."

They run.

11:23 PM. ANOTHER HALLWAY.

The fourth Doctor does, indeed, have teeth and hair. Down to a very tattered pair of trousers and a mucky dress shirt, none of his hems anywhere near his extremities, he looks like a particularly deranged scarecrow. Rose laughs herself sick.

"I'll have you know this me was quite popular with the ladies," the Doctor drawls.

"Which ones?" Rose wants to know, "Circus performers?"

"Those, too," the Doctor admits ruefully, and fluffs at his wild hair. His voice is deep and musical, not unlike his Ninth's-- and it's interesting, those little parallels. She wishes she had a camera. She wishes they had more time. She wishes--

"Come on, he's gaining on us," the Doctor says, his hands rough on hers and a little hairy, "My next few bodies are going to slow us up a bit."

11:32 PM. AN EMPTY BALLROOM.

She almost doesn't notice the change until they have to take a break. Her feet are killing her, even though she picked her most sensible dress shoes, and she can feel blisters forming from the straps.

"Oh no!" she blurts out when she straightens up, "You're old!"

The Doctor looks at her mock-sternly, the faintest twitch of a smile tucked in the corner of his mouth. "I am a very spry three hundred right now, young lady, and I'll thank you not to make accusations."

"Sorry," Rose apologizes, fighting her own smile, "It's just-- the hair. You look like someone's grandfather all of a sudden."

The Doctor winces, going pained and gray and distant all at once.

"Oh god." Rose reaches out for him blindly, horrified. "You were, weren't you?"

"Not at this point. Not anymore," this Doctor says. His smile has crystallized into a false, brittle thing, and doesn't suit him. He tucks his hands awkwardly into his pockets.

"Doctor..."

He makes a distant, elegant sort of shrug, as if sadness were a cape round his shoulders. On this Doctor, gray and craggy as a mountain, it suits him. "Not my first loss, Rose. Nor my last."

She takes his arm, gently, rests her head against his tall shoulder. He's taller than her usual Doctor, as tall as the Fourth one, and she feels so much smaller up against him.

"Did you think about her?"

"I liked to think that she was happy."

"Was she?"

A howl sounds in the distance, echoing through the still, dark space.

"Let's get moving," the Doctor says gently.

Rose shivers. "Lets."

11:43 PM. THE WEST WING SOMEWHERE; LOST.

His second body looks rather like someone had taken his Ninth self and shrunk him in the wash. Their matched strides go from parallel to perpendicular to in a flat second as the Doctor goes spiraling downwards, and Rose trips over him. They both go sprawling.

"Oh, crumbs, Rose, are you alright?" the little man asks, and reaches to help her up. For a given value of up.

"I wasn't expecting the, er, the..." Rose waves at their legs uncertainly.

"Yes, well." The Doctor scowls fiercely (one of his best scowls yet) and smooths down the front of his dress shirt. It's tight across his shoulders again, but now it hangs nearly to his knees, and his trousers are pooling at his feet. "This incarnation of mine was rather, ah, concentrated. Why do you think Three and Four were such beanpoles?"

Rose laughs. "When you overcompensate, Doctor, you don't do it in halves."

"Don't be cheeky," the Doctor scowls. It's as if this particular face was made for scowling. "I'd like to see you do better on your first regeneration."

"Maybe I will," Rose retorts. Then, "Hold on, so we're nearly there?"

"Oh my, yes. Soon enough I'll have regressed to my first body, and won't that be exciting." This time the Doctor grimaces. "A stodgy, half-dead old coot."

"You don't get along well with yourself."

"My first self didn't get along well with anyone," the man protests. He gives an abrupt and startling wry smile. "I do suppose I'm a creature of habit."

She nudges him affectionately with her shoulder. He reverts to scowling. They walk in silence for a while.

"Rose?" He says after a moment.

"Yes, Doctor?"

He catches one of her hands in both of his and peers up at her, oddly intent. "You won't let me treat you roughly, will you? When I'm him?"

"Of course not, Doctor," she says, oddly touched. She places her free hand on his, strokes across his knuckles. What must it be like, to change so much that you can't even trust yourself to feel the same way about people you love?

He nods, suddenly a bit taller and a great deal older. His last, first body.

"Hmm, well then," he says, tucking her arm in his. "Come along."

11:50 AM. NEAR THE KITCHENS, PERHAPS.

The final Doctor is more like someone's grandfather than ever. He hobbles gamely along, leaning on her arm. He's heavy, but Rose can't bring herself to complain.

"What I wouldn't give for my old walking stick," he puffs, his voice reedy and thin. "Where are we?"

"Under the kitchens, I think," Rose says. "Maybe there's a storeroom-- yes!"

A nice, solid, locked door. The Doctor fumbles his sonic screwdriver out of his sleeve and promptly drops it.

"Blast," he wheezes. "These old hands-- I don't remember if I ever used a screwdriver with them. I don't..."

"It's no matter," Rose says, scooping the tool off the floor. "Tell me which setting."

"Setting forty-two. Just rotate the ring around one and a half times and hold the button down."

She does, the lock clicks, and she holds the door open for him. He shuffles through, a smile like a grimace on his pained, loose features.

The storeroom is cool and dark around them, and they both relax a little. Rose takes a moment to study this new Doctor, this first and final version of the man she loves. It feels like finding the missing prologue of a favorite story, of suddenly glimpsing what some author meant to start out with, before they knew where they were going to end up.

It's strange.

"What is it?" the Doctor asks, and Rose realizes she's been staring at him for a while.

"Sorry, it's just-- you've got these sad eyes," Rose says, and reaches out to him. Her hand feels so warm against his cool, old, papery skin. "You-- all of you've had such sad eyes-- I thought maybe you were happier when you were younger."

"They didn't go in for that sort of thing on Gallifrey," the old Doctor says, and tilts his face into her palm.

"Being young?"

"That, too."

Rose helps the old man sit down on a box, his hands in hers that kind of soft-and-hardness that comes with age, with loose skin over brittle bones. He's breathing hard, and his knobbly knees are trembling a little.

"This is your last one?"

"Indeed, yes." The Doctor leans against her a bit. "From here matters should progress linearly." He feels so fragile, even as he also feels just like someone she knows, and it's strange but not entirely awful.

"You're so old," Rose says quietly, meaning all his lives and meaning this man, here, before her.

The Doctor laughs, a hoarse, dry cough of a sound. "Arrogant, officious, demanding: I was so young! Mm. Tramping around the universe complaining that the food wasn't any good and the service was shoddy and kids these days played their music too loud." His eyes twinkle at her, sad, yes, but mischievous and familiar and oh, it's still her Doctor.

"You must have driven your poor companions mad," she agrees, grinning.

The gnarled hands squeeze hers. "Mad?" The Doctor demands, leaning forwards conspiratorially, "Mad? My dear girl, I drove them 'round the bend."

Rose laughs and rests her forehead against his. "That's my Doctor," she says fondly.

"Oh, Rose." The Doctor says, and for all that his voice is low and hoarse it's warm, too. His eyes drift closed. His face already looks younger, like a sheet being pulled smooth.

"Hmm. I do think I'm ready to go on. We need to find somewhere safe enough for my regeneration-- my reincarnation, as it were."

"Onwards, then," she says.

The Doctor slides carefully off the box, his eyes clear and sharp, his nose like the prow of a ship. There's something predatory about this body of his, something that invokes the sharp, wild brightness of his Tenth body, of all of his bodies. It is in this one especially as his limbs fill out and he stands straight and proud by her side, it shines forth clear and strong, as if each body after this one was a copy, and then a copy of a copy. He smiles at her like a lion might, and she can see in it the ghost of a man who was strong enough to turn his back on everything he knew and run, or at least stagger off, brave enough and mad enough to become something entirely new. Someone who was never too old to change.

"Onwards," he agrees, and offers her his arm.

They go.

11:59 PM. THE EMPTY RECEPTION HALL.

"I want you to hit me," the child says, "as hard as you can."

"Oh, god." Rose says. The length of broken-off pipe is cool and very heavy in her hands. "I don't think I can."

"Rose, we don't have time for dithering! If I regress to before I was exposed to the schism, I won't be even half a Time Lord anymore-- I'll never get back, I will die."

"But you're a little kid!" Rose protests, although she knows this is ludicrous. The child gives her a look that says quite clearly that he knows she knows, and he knows she knows he knows, and she'd better get on with it.

She hates that she knows the Doctor well enough to read his expressions this well even when he's a bitty little blond Time Tot with an awful pudding-bowl haircut and a nose that (she now knows) he will never properly grow into or escape from. She hates that she doesn't know the Doctor quite enough that she can believe this little boy is really him, not really.

"I hope you're sure about this," Rose says. "I don't know if this counts as infanticide or, or-- old personcide."

"Geriatricide," the child says precisely, and points at the back of his head. "And in this case, I believe it would be more properly termed obstetrics. Come now, one good smack."

"Are you sure you're Time Lord enough for this?" Rose demands.

"Only one way to find out," the child says, and there's just enough of a mad spark in his smile that she believes him. He's her Doctor.

Rose curses through her teeth, grips the pipe firmly, and swings.

The child's head comes apart in a spatter of blood and golden sparks, and out of his crumpling form something explodes, growing like a sprout from a seed, like a phoenix from a flame.

January 1st, 2010, 12:00 AM. THE SAME RECEPTION HALL.

When the light fades, the Doctor still looks different. Not entirely different-- he still has a wild shock of brown hair, still pale skin and long fingers and-- yes-- that mole. But it's as if someone has taken a funhouse mirror to his tenth face and then left him like that. His chin is too large and his forehead is smooth and rather wide and his eyes, when he blinks them open, are a new color, a muddy brown-gray-blue like a kitten's. But it's funny, also: he's familiar, this boy, and she's seen these bits before. He has Two's nose, and Eight's lovely cheekbones, and when he smiles uncertainly up at her he's all Doctor, her Doctor.

"I seem to have gotten off a stop too far," he murmurs, and his voice cracks and pitches up unevenly, "do I still have legs?"

"Yeah," Rose says, tries to smile past the scream sitting in her throat. "I didn't hit you too hard, did I?"

"You hit me hard enough," the new Doctor mutters. He rubs dazedly at his forehead. "Oh, Rose, I'm so sorry. I've gone and changed on you again. My head."

"New, new, new Doctor," Rose agrees, and pushes him back down when he tries to sit up. "Hold on, how many fingers am I holding up?"

The Doctor focuses on her, or tries to. "Lots," he pronounces. "Lots of fingers."

Rose looks at her two fingers. "That's...okay, we're going to work on that."

Meanwhile, the Doctor has discovered his hair. "I'm a girl!" he squeaks. "No!"

"You're not a girl."

"You'd tell me if I was a girl, right?"

"Yes, Doctor." She hauls him to his feet.

"Nothing against your gender, Rose," the Doctor babbles, "I think girls are just lovely, but I'm too old for, for, oh, bras and knickers and lippy and such. I gave Sarah Jane a sonic lipstick once, did I tell you? I couldn't ask for it back, that would be rude! I would be old and rude and a girl!"

"You're not a girl, Doctor," she tells him patiently. The new Doctor is very much male (she checked-- she's only human, after all), and surprisingly heavy. He's tall enough to give the impression of gangliness, but he's really quite solid.

"Am I ginger?" he asks hopefully, still leaning all his weight on her.

Legs buckling, arms straining, Rose grits out, "We'll buy you some hair dye, Doctor. You can be any color you like."

"You're so clever," the Doctor beams, and kisses her until she's dizzy.

"Put your shirt on," she tells him, but she's smiling for real, now.

He puts his shirt on, unsteadily, and then stands there looking like a very uncertain gigolo.

"You look like a stripper," Rose says. "We can't go back to the party like this."

"Where's my bow-tie? " the Doctor says, and glances around. "I could be a Chippendale. People would cheer and throw peanuts. "

"No, Doctor." Rose tugs on the hem of his shirt, but it won't cover him properly. He might not be much taller than before, but he certainly isn't any shorter. She wishes they'd kept his trousers, but they're back somewhere around the kitchens. They hadn't planned this very well. Then again, this was the Doctor, and when it came to plans, hiding somewhere while his companion broke his head in with a pipe constituted a really deviously clever piece of scheming. After all, it had a whole two more steps than 'run away from anything trying to eat you'.

God, she is turning into her mum.

"I think I might fancy peanuts this time around," the Doctor remarks, petting her head, daft as ever, "and bow-ties. Definitely bow-ties."

"How do you feel about kilts?" Rose snaps.

"I was born for kilts," the Doctor says in his Scottish accent, and strips his shirt off.

He's so lucky he's cute.

12:01 AM. STILL THE SAME RECEPTION HALL.

Rose is tying the shirt as neatly as she can around his waist, tucking in the sleeves and the bloodstains, when the Doctor's hands go tight and urgent in her hair.

"Rose," he says urgently, and his new fingers (soft and wide and strong) slip into hers. They fit perfectly. She is very aware of the heat of him, the new/familiar smell, the tense muscles of his thighs.

And Lazarus the scorpion monster behind her, his hot wet breath on her neck.

"Yes, Doctor?" she asks calmly.

"Run!" he shouts.

Somewhere in the future, they are going to sit down and talk about this like adults, and he'll tell her what this all means, for him and for them and for her, and somewhere in the future maybe there will be shouting and crying and explaining things to her mum. But for now, his hand fits perfectly in hers and there is a giant scorpion monster howling through the hallways, trying to eat them.

12:02 AM. IN TRANSIT.

Laughing like madmen, like children, they run.