Author's Note: My chapters on this are likely to be fairly short (unless I get carried away. It happens.), but these are where the natural breaks fell when I was outlining. My schedule has been crazy lately, so I can't promise as fast updating as usual, but since "usual" for me is a chapter every 1-3 days, there still shouldn't be too long between chapters. I expect six chapters altogether.

This started as an askbox fic for Re-sile, and I wouldn't have written any further if she hadn't encouraged it.

Beta, as usual, the awesome Scullywolf.

Chapter One

Fog crept slowly through the dark cemetery as Buffy Summers circled what looked like a blue phone booth, one that she was sure hadn't been here at her last visit. "Police Public Call Box," it read at the top, and Buffy spared one more glance at the words before continuing around the corner of the box.

She heard a deep growl and raised her stake, raising it just in time as the vampire she'd been tracking lunged at her. With one smooth, practiced movement, she plunged the sharpened wood into her attacker's chest, deep enough to reach his heart. She took a moment to wonder at the fact that vampires still managed to look shocked every time she bested them, trying to decide whether it was the whole "teenage girl" thing or just arrogance, then watched him turn to dust, the resulting pile nearly impossible to see in the high grass and low light.

Beside her, the police box opened, and Buffy readied her stake again, stepping back so she could see more clearly around the wooden doors that hadn't fully opened. A man stepped through, staring at something he held in his hands, frowning. Almost automatically, Buffy took in his clothing; judging by the brown, pinstriped suit and the red converse, his fashion sense hadn't developed locally.

Seeming oblivious to her presence, the man started speaking.

"I'm certain there was someone out here with large traces of rift energy. Well, fairly certain." He paused, smacking the device firmly before twisting a dial. "There are abnormally high ambient energy readings, too. Then again, maybe that's what attracted whomever was here. I know there's a rift nearby, but concentrations that high away from its center are unusual. It's gone now, though, as if what was containing it was destroyed, since there's no indication of teleport or temporal shift," he said, looking behind him into the box and shaking his head before turning back to the device.

Buffy raised her eyebrows, wondering who he could be talking to. It wasn't like there could be much space in there. If she could just take a couple steps to the side…

As she shifted her weight to try to see inside, the man finally seemed to notice her. His eyebrows shot up, and he grinned.

"Hello!" he said, sounding as if he'd had an unexpected surprise. "I was just studying the energy emitting from the nearby rift. It does seem to attract a lot of," he stopped, seeming to rethink what he was going to say, "visitors, doesn't it?" he finished. He looked around, seeming to see his surrounding for the first time. "What year is this? 1998? 2000?"

"It's '99," she replied, tightening her grip at the confirmation that this guy hadn't been around humans for a while, at least not long enough for conversation or things like keeping track of the date. Usually, that meant just one thing: vampire. "And I'm the Slayer."

His friendly smile dropped.

"Slayer? Don't usually get along too well with those who try to kill others," he said, his light tone clashing with his blank expression. Something in his eyes made her suppress a shiver. Buffy didn't exactly scare easily anymore, hadn't for a long time.

"Not a slayer, the Slayer," she clarified, continuing when he arched one brow. "You know, 'one girl in all the world to fight the vampires and demons and forces of darkness.'"

O~O~O

The Doctor studied the petite blonde in front of him. He never did care to judge based on appearance, of course, but this girl looked like she'd feel more at home in a cheerleading outfit than in a graveyard, fighting.

"So, what kind of demon are you, anyway?" she said, ponytail swaying as she fixed him with a glare.

"Demon?" he responded, absently putting the Locational Minimizer inside his jacket before shoving his hands into his trouser pockets. "Been called a lot of things, but it's been I while since I was called a demon."

He quickly went through a mental list of possibilities. Rift energy attracting other species was certainly not without precedent. This was well before the general public had knowledge of aliens, so it was possible this girl had mistaken alien visitations for demonic activity. That combined with the strange readings he was getting from this particular rift, ones that, if he was correct, and he usually was for this sort of thing, would enhance aggression in several of the less-friendly long-term visitors, meant that this "Slayer" had almost certainly had negative experiences with non-terrestrials.

He'd heard the term before, of course, with rumors of Slayers dating back to well before history was recorded in books, typically associated with "vampires," but he'd never actually met someone who claimed to be a Slayer. He'd attributed the whispers of information to humans who encountered aliens or time travelers or both; it seemed that was the explanation for most things supernatural in this particular time period.

"Don't even try to tell me you're human," said the young woman, rolling her eyes as she continued their conversation, "cause my spidey sense is tingling."

He concentrated for a moment and had to suppress an audible reaction to her timeline; it was intertwined with the fate of the entire world. He'd never seen a human quite so singularly important before, and if he hadn't been looking for it with a hint of who she was, he was fairly certain the unusual size of her impact would have blended in entirely to the background and she'd have appeared completely normal. He didn't see timelines quite as well as he had in some regenerations, but he was fairly certain he'd not encountered this kind impact from one person, at least not for a very long time.

"Well, not human, no, but then, neither are you exactly an ordinary human, based on what you've said," he told her, nodding to himself. Despite her willingness to kill without even understanding what it was she was killing, she had made no move to attack him. She didn't seem to be the sort who resorted to mindless violence, and this made him much more willing to give her the benefit of the doubt in their interactions. "I didn't catch your name, Slayer of Vampires."

"It's Buffy," she said, raising her chin slightly as if in challenge.

"Hello, Buffy," he said with a grin. "I'm the Doctor."

"The Doctor?" She arched an eyebrow at him. "That anything like the Master?"

His grin slipped. The Master shouldn't be here, not in this time and place. If he was...

"You know the Master?" he asked.

"Knew him, staked him, consecrated his remains, the usual," she replied.

"Oh, yes, vampire, right," said the Doctor. He attempted to put his smile back in place and returned his focus to the person in front of him.

"You haven't told me what you are yet, Doctor," she told him.

"Alien, of course," he replied. "Well, to you. You're the alien to me. Since we are on your native planet, though, I suppose it's more accurate to call me the alien. Time Lord, specifically."

"Huh?" Buffy was leveling him with a look that would probably wither a perfectly healthy plant, her grip on the stake tight despite the fact that she'd finally lowered it. "Aliens are real?" she asked.

"More real than what you call vampires," he replied. "Most mythological species that exist on your planet are, in fact, alien species, or at least alien hybrids. At any rate, I wouldn't say it's accurate to call them vampires."

Buffy crossed her arms, effortlessly avoiding staking her arm. The Doctor noted that the stake seemed to be an extension of her arm, something she didn't need to consciously think about in order to use.

"And what do you call vampires, then, Mister Alien?"

"Well, there are all sorts of different species you lot mistake for vampires. This particular sort of 'vampire,' though," he eyed the pile of dust near Buffy's feet, "probably Dammusks. They reproduce by taking over the bodies of the previously living, correct?"

"Duh. Vampire," Buffy appeared unimpressed, and the Doctor wondered briefly how much this young woman had seen in her life. "You know, demon inhabiting a person's body."

"Well, alien inhabiting a person's body," he corrected. "They bind to so much of their host that it renders the body unable to maintain its original form after the parasitic life form has been removed, hence the pile of dust. There are other species who reproduce in a similar manner, certainly, but the Dammusk is easy to spot when it's deceased."

Buffy arched an eyebrow at him.

"Still don't believe you're alien," she said, glancing down briefly to flick some dirt from under a nail before returning her gaze to the Doctor.

Her eyes held so much. The Doctor held his breath a moment as he was again forced to think of his people, so often so very old in bodies that didn't match. Buffy had seen more darkness in her short life than anyone should have to. Yet, she still seemed to be clinging to what light she could find. She hadn't crumbled, hadn't holed up in despair. Her body language and her manner of speaking both declared the same thing: Buffy was tougher than anything life could throw at her. He thought for a moment, then came to a decision. Maybe he could show her that not all aliens-even if she hadn't been aware they were aliens-were intent on harming others.

"Want to see my ship?" he asked, beaming at her. In return, she stared until he started to feel uncomfortable. "Have I got something on my face?" he asked, rubbing a cheek to check.

"Lemme guess," said Buffy, "your spaceship is that phone booth?" She nodded at the TARDIS, and he realized that with where she was standing, she'd been unable to see inside.

"Yup," he replied, smile growing even wider as he anticipated her reaction once she saw the interior. He turned around and took a few steps in, then looked over his shoulder and waited for the Slayer to join him.

O~O~O

Buffy watched the skinny man walked into the box and sighed.

"Isn't it a bit small for both of us?" she asked as she walked toward where she'd lost sight of him. "I mean, not that I've never gotten cuddly with a demon," she muttered, "but…"

Buffy felt her mouth continue moving, but no words were coming out as she stared. The inside of the box was much, much bigger than it looked on the outside. She leaned to one side to check the outside again, then straightened. It didn't appear that it was underground, either, which would at least explain things. Plenty of tombs were bigger underground than above.

"It's…" she started, taking another step forward, stopping before actually setting foot inside.

"Bigger on the inside," he finished, sounding as excited as Willow did when she was playing with a new computer thingy.

"And this is your space ship?" she managed, gathering her brain again.

"Yup!" the Doctor answered, popping the P and moving further inside. He looked over his shoulder again when she didn't follow him immediately. "Come on, then."

Buffy took a breath, checked to make sure nothing was amiss in the otherwise deserted graveyard, then took a step into what she'd mistaken for a phone booth.

She wasn't sure whether the Doctor was crazy or whether she was the crazy one, but definitely one of them was crazy.

She couldn't wait to tell Giles.