Disclaimer: This story takes place somewhere between the 5th and 6th series of the New "Doctor Who." All major characters and alien species are owned by the BBC and by their respective creators/actors unless otherwise stated.

Also, I have made some edits to the first 2 chapters just now (October 2014) since they were originally published in 2011. Nothing too major, though. In any case, please enjoy!

Double Digits

Chapter I: Two Doctors, Three Companions

"Well, now, that was fun," said the Doctor as he exited his bright blue TARDIS. He seemed remarkably chipper for someone who, barely an hour previously, hadn't existed in any form other than a glimmer in the memory of the ginger-haired Scottish girl who followed him out of the box. Then again, he had just been at the girl's wedding; it was probably impossible not to be cheerful after dancing around in a totally crazy manner, as he had. He had changed out of his tuxedo into an outfit he found far more appropriate and stylish – a grey tweed jacket, matching slacks, and of course, the ever-essential crimson bow tie.

"Where are we?" asked Amy Pond as she emerged from the TARDIS. She was still wearing her wedding gown, but had taken off her veil. Her new husband Rory Williams followed her out, dressed in his tuxedo and glancing around at the darkened city streets. It was clearly nighttime in London, but the Scottish girl's real question was meant to be more along the lines of when they were.

"London, 2009. Right around Oxford Circus. Not fair; I wanted to go someplace awesome!" yelled the Doctor, though the excited grin on his face betrayed his curiosity. The TARDIS, in all his centuries with it, had never taken him anywhere boring, after all. That wasn't always a good thing, of course; he couldn't even remember the last time he'd had a trip where he didn't spend at least half of it battling or running from some interstellar menace. Still, with any luck, they'd be able to enjoy a few minutes of relaxation before having to run for their lives.

"What's that?" asked Rory, looking up. The Doctor and Amy followed his gaze to see an amazing sight: a Routemaster double-decker bus with the upper level apparently smashed in. That in itself was remarkable enough, but was a detail that almost eluded the three onlookers due to the fact that the bus was flying.

"Well, now, wasn't expecting to see that again," muttered the Doctor as the bus turned around in midair and prepared to descend.

"What . . . ? How is a Routemaster flying?" Amy asked, bewildered.

"'Cos I made it fly." The Doctor grinned slightly, proud that his handiwork had impressed his companions even when they hadn't been there to see him do it.

"And dare I ask why the top level's all smashed?" questioned Rory.

"Bit of trouble with a wormhole. Nothing major – passengers survived. Driver, on the other hand, wasn't so lucky," added the Doctor, remembering the poor fool who tried to run back to Earth after seeing that they were on an alien planet. Obviously, a person thinking clearly wouldn't attempt to run through a wormhole without adequate protection. Especially after seeing that the wormhole could pulverise a double-decker bus.

The bus touched down and two figures stepped out: one who the Doctor expected, and the other who he most certainly did not. After all, he did play a part in this very event not long ago, by his reckoning. Then again, he was anywhere from 700 to several thousand years old. (Even he couldn't remember his own age; and besides, would he measure his age in Galifreyan years or Earth years?) In any case, because of how long he had lived, all the time he had spent traveling with human companions didn't feel very long to him at all; the most joyous moments always fly by the fastest, after all. He had to admit, though, that the few hours he'd spent in the Pandorica felt like an eternity – even worse than the year he'd endured (and later erased) as a captive of the Master. At least the Master played decent music; in the Pandorica, all the Doctor had had were his own despairing thoughts.

The first person to exit the bus wore a stylish black catsuit and boots to go with her long, dark hair; the Doctor recognised her immediately as Lady Christina de Souza, the treasure thief who'd helped him to get the bus back to Earth. Though he'd turned down her request to be his companion at the time because she stole treasures for thrills, the Doctor now had to admit that he had just been fishing for reasons not to take anyone on as a companion; after all, hadn't he "borrowed" the TARDIS for similar reasons?

The second, much less expected figure stepped out of the bus. "And I helped him transcribe his play. Didn't ask for coauthor credit, though; that might've been a bit much," said the man in a pinstriped brown suit, speaking in an Estuary English accent as he finished a sentence. "By the way, I'm told the fellow who played Hamlet last year looked a lot like me. Funny how that happens!"

The Doctor couldn't believe his eyes; standing right before him was . . . well, him! His previous incarnation, to be more precise, but still . . . why would the TARDIS have brought him here and risked an irreparable time paradox? And more importantly, at least to the present (or, more accurately, future) Doctor . . . did his hair really look like that back then?

Before the Doctor could say anything to his companions, though, his previous incarnation spotted him. It was clear from his gaze that he recognized his future self to some extent – at the very least, he could tell that they were both Time Lords. "Well, hello!" called the past (or present) Doctor. This is getting confusing, thought the present-or-future Doctor, whose brain seemed to be attempting to transcribe the encounter. Sometimes he couldn't tell why it was transcribing his life that way – it was almost as if he was preparing to write up his adventures and post them on the Internet or something.

"Who's that, then?" asked Amy, eyeing the newcomers to the scene (particularly the man in the pinstripes) curiously.

"Well, the lady is a friend I made a while back . . . Lady Christina de Souza." The woman in black gave a slight bow and flashed a mischievous smile at the new (to her) incarnation of the Doctor.

Amy noticed and giggled. "Doctor, you naughty-"

"And the gentleman," continued the present-or-future Doctor in a somewhat louder tone, interrupting her, "is me. Before I looked like I do now, obviously, but yeah."

The redheaded girl and her husband blinked, and she took a few seconds to respond. "But you look younger than he does!" Amy exclaimed after a moment of stunned silence.

"So . . . you can change your face?" asked Rory.

The present-or-future Doctor put a hand to his temple. "Okay. Long story short, if I die, I can regenerate. It's happened a fair few times now. New face, new personality . . ."

"New fashion sense?" asked Amy curiously, appraising the past-or-present Doctor's outfit. This chap certainly wasn't raggedy, though she recognized some articles of clothing as being less beat-up versions of what she had first seen her Doctor wearing.

"Is that a bow tie?" The past-or-present Doctor raised an eyebrow at his future self's choice of attire.

Amy laughed. "There was one time he decided to wear a fez, as well!"

"Oh no," the Doctor in the brown jacket snickered. "That really gives me confidence for the future!"

"Hey!" exclaimed the Doctor who had a taste for clothes that Amy seemed to find strange. "Bow ties and fezzes are cool, all right? When you're me, you'll learn," he said to his past self.

"Well, I suppose I shouldn't talk," replied the Doctor who was (in Amy's opinion) more stylishly dressed. "After all, I . . . well, we . . . used to wear a stick of celery on my jacket, didn't we? And before that, the scarf . . . those were the days, weren't they?"

Rory interrupted before the two Doctors could continue. "All right, you two, stop talking to yourself! So then . . . what regenerations are you?"

"I'm number ten," the past-or-present Doctor said, raising a hand.

"And I came right after, so I'm eleven," said the other, raising his hand in a similar manner but also wiggling his fingers to an absurd degree. Ah, much better, he thought in response to having definite numbers to label the two Doctors by, as his mind was still acting as stenographer for their meeting.

Ten looked at his future self a bit sadly. "So . . . that means that before long, I'm gonna be you."

Eleven gave a solemn nod. "You got the warning about someone knocking four times, then?"

"Yeah."

"It'll be hard. But you don't have to worry. It turns out okay . . . just do what you know is right, and it all works out. I mean, being me isn't bad at all."

Ten noted the sincerity with which his future self spoke. "Thanks for that. It's what I needed to hear, I think. And I still get to have some good times before I go, right?"

"Oh yeah, of course! And afterward, as well – apparently, I'm brilliant at football. Even though we'd never played before, which is a little weird."

Ten turned to Eleven's companions. "And you've got a redheaded runaway bride of your own! Guess the impression Donna made on you – me – hasn't gone away quite yet." There was a hint of sadness edging back into his voice.

Amy mouthed the word "Donna?" while looking at Eleven curiously. She had asked the Doctor once before just how many previous companions he'd had and how many were attractive, young women, but he had refused to give her a straight answer.

Ten didn't seem to notice, however, and paused for a moment, his sorrow apparently gone just as fast as it had come. "Redheaded runaway bride . . . redheaded runaway bride . . . Wow, what a tongue-twister! And why is it that you – that's to say I – still don't get to be ginger, but your companions are?"

"Excuse me, um, Doctor Number Ten," Rory butted in. "But she's not a runaway – she and I married just before we came here!"

Ten stared at the newlywed nurse. "You know, you remind me a lot of a guy I knew named Mickey. Before he got awesome, that is."

Rory scowled. "Thanks for that."

"No, he was a nice lad. It's a compliment! Well, kind of." The Tenth Doctor shrugged, but after a moment, his eyes widened. "Hang on . . . Are you, or have you ever been, an Auton?"

Eleven rolled his eyes. "Yes, yes, long story. Anyway! I think we'd better be off. Don't want to create an even bigger temporal paradox that'll destroy . . . wait a second." He glanced over at the bus. "I never landed here after the bit with the wormhole and all that."

"Of course not," said Ten matter-of-factly. "That was a week ago. Well, roughly a week. Time traveling and all, you know."

"No, that can't be right. I left here right after letting her go." He indicated the raven-haired burglar who was waiting by the bus, stealing long glances at each Doctor in turn. "Then I saved the poor bloke who accidentally insulted a Judoon officer – simple misunderstanding. And then I had a spot of trouble with some Cybermen who'd turned up at the first landing on Titan in 2042, then tea with Voltaire, couple of other things, then the whole thing on Mars . . . ooh, I shouldn't be telling you that, should I?"

"Don't mean to interrupt, Doctor . . . er, Doctors," Lady Christina interjected as she stepped away from the bus to face the two Time Lords. "Shouldn't bad things be happening to the space-time continuum or something if there are two of the same person from different times chatting with each other? At least, that's what you told me when we went to meet my mum." The meeting with Christina's mother had, in fact, taken place when she was twelve in the normal continuity, and so the Doctor – at least, her Doctor – warned her not to interact with her younger self.

"She's right," replied Ten, putting on a pair of glasses for the sole purpose of looking more academic. "The fact that the universe isn't tearing itself to shreds right now means that something's different."

"Like what? What do you mean?" asked Amy, staring at Ten in a way that made Eleven and Rory shoot irritated glances at both her and the object of her new curiosity.

Ten raised his eyebrows. "Well, it's obvious, isn't it? Somewhere down the line, one of us ended up in an alternate universe – a different reality from where we belong."

Eleven took a step toward Ten, and the Doctors then took a look at each other's respective companions; Ten glanced at Amy and Rory while Eleven met Christina's eyes. Then, as if they'd planned to say it all along, the two Doctors yelled at each other in unison:

"I'm the real Doctor! You're the alternate!"

Author's Note: Stay tuned for the next chapter, in which all will be revealed . . . or not. Or perhaps some new mysteries may surface. Time will tell! In the meantime, please read and review.