A/N: thank you to everyone who has reviewed and faved so far! Part 4 took me a while, as you may have noticed. I wrote two beginnings and couldn't decide which to go with. The second beginning is now the middle, and the first is... well, the actual beginning.

This is going to be a bit longer than I originally planned. I swear, I'm almost incapable of writing one-shots.

Words: 1,588 (this part)
Summary: The Winchesters meet the TARDIS, and the Doctor is rebuffed.

Dean scrunches up his nose and looks the blue box up and down. "It's a Police Box," he says, looking to Amy with an expression of expectation, as if he thinks she's about to burst out laughing and admit that of course they're just kidding, there's no such thing as time travel!

"Yes," says the Doctor. "That's what it looks like on the outside. It's... stuck that way. It really is a time machine, though- a TARDIS, which stands for-"

"Time and Relative Dimension in Space," says Amy slowly. She likes saying the words; they still sound so promising to her, just like the first time she heard them.

"You're pulling our legs, right?" Sam says.

"I'm not, but if you want to believe that then I suppose there's no point in looking inside. I like open-minded companions, you know."

The two brothers exchange a glance. Sam stuffs his hands in his pockets and Dean shuffles his feet a little, but neither make a move to leave. The Doctor's face splits into a wide grin and he pushes the door of the Police Box open. Golden light spills across Sam's face, and his eyes widen a fraction. He moves forward, pushing the door in further, raising a foot to step inside.

Dean follows him and Amy grins as she hears the two of the make some very satisfactory exclamations, although she tries to ignore that most of it is made up of swear words. She follows the Doctor inside and shuts the door behind her, watching as Sam and Dean look around in awe.

"But... how?" says Sam. "How can it be bigger on the inside?"

"Er, something about a big box and a little box, very complicated! Most people don't ask how, you know. They just say it is. That's refreshing. Don't touch that!"

Dean moves his hand away from a big purple lever and looks around sheepishly at the Doctor, who's giving him quite a stern look.

"I think it's best that we get past the whole "oh golly, a time machine!" phase. Now that you've seen that I'm not mad, or at least not completely, you'll have no qualms letting me help you! I can be quite useful, you know. Lots of experience and all that..."

"Lots of experience?" says Sam. "You don't look very old."

"No. Not this time anyway."

"Huh?"

"Oh, I didn't tell you? I'm an alien, too- well, alien to humans, not alien to Time Lords. You should have guessed that; since when did humans have time machines? Anyway, I'm 920 years old, I think. Time can be hard to keep straight when you're... a time traveller."

"Wait," Sam says, suddenly looking quite overwhelmed and not at all sure of which point to address first. "You're an alien? Is she?" he points at Amy.

"No, she's just a human-"

"Hey!"

"But she's not entirely useless and that's why I let her stick around. I'm from a planet called Gallifrey. Although it's gone now. Has been for rather a long time."

Sam leans back against the console. "This is insane!"

"You're telling me..." says Dean, who looks quite pale.

"Any more questions?" says the Doctor.

Amy thinks the two of them have enough to digest already, but the tall one, Sam, seems to have an insatiable hunger for information. Even his brother gets bored after a while and leaves the console room to explore. Amy follows him, not wanting him to get into trouble.

"Holy crap, this thing has a swimming pool!" he says, closely followed by, "Are those bunk beds? Bunk beds, in a time machine! This is unreal..."

"Yes, well, we need somewhere to sleep."

"You bunk with an alien?"

"No," she says, looking down at her feet. "The bottom one was my husband's, before he left."

"Oh, I'm sorry... so you're divorced?" Amy pretends not to notice the hope on his face.

"No, he just wanted a break from all of this," she says, gesturing vaguely.

Dean nods and looks around the little room that Amy used to share with Rory. "What's it like?" he says suddenly.

"Oh, it's amazing," she says.

Dean raises an eyebrow. Amy sits on the bottom bunk and he lowers himself carefully to sit next to her, and waits.

"I met him when I was a little girl," she says. "And then he left me for a long time- not that he meant to; it was an accident- but I never forgot him. And then he came back and all of a sudden I'm travelling time and space and it's so overwhelming, you know? You wouldn't believe how much there is out there. It's actually kind of frightening."

"I know what that's like," he says. "In a way."

"I hadn't been on Earth in months, until now," she sighs.

"I don't think I would be either, if I had a time machine."

She stands up suddenly, looking rather sad. "Come on, I'll show you the rest of the rooms."

ooo

"Let me get this straight: you regenerate every time you're about to die?"

"Yes. It's a painful process, too. And you never know what you're going to get."

"So you live forever?"

"No, sometimes the damage is too great and even regeneration can't save a Time Lord. Some things you can't come back from. Who would want to live forever, anyway?" His eyes, Sam notices, look much too old for his face. He sees a deep sadness in them, and a great wealth of knowledge.

Sam stares at him thoughtfully. He could tell this Doctor that death in his life isn't always permanent. He wonders what he would say about that, but for the sake of simplicity doesn't mention it. The man looks quite pale enough as it is. Something about him suggests that he's not used to disembowelment, so Sam just nods, deciding to keep the more gruesome details of his life to himself.

"Why don't we find the others?" Sam suggests. "Then we can figure out what to do."

ooo

It's only just midnight when Sam steps out of the TARDIS. The wind is gone and sprays of stars have appeared in the sky, along with a small sliver of moon. He pulls out a sleek black phone and presses the number one; Bobby's number, on speed-dial. The phone rings only a few times before Bobby picks up and gruffly greets him.

"Bobby, it's Sam. We've, uh, come across something- someone... new." He clears his throat, frowning.

"So what're you calling me for? Research? 'Cause I was just about to go to bed."

"Actually, I think we already have all the information we need. He told us."

"He told you? What is he?"

"He says he's from another planet."

"Well that sounds like a load of crap. And he didn't jump you? Throw you around? Nothing like that?"

"Nope, we all sat in a circle around the campfire and had a nice little chat. Me, Sam, him, and his redhead girlfriend."

"You're gonna have to explain properly, Sam, or I'll hang up on you. I'm tired."

"Alright, listen. This guy claims to be over 900 years old. He says he's from a planet somewhere- as in not Earth- and he said, get this, that he can travel through time. He even showed us his 'time machine'. It's this blue police box, like the ones they had in the 50s. It's full of weird gizmos and random rooms, and..."

"What?"

"It's bigger on the inside."

There's silence on the end of the line. Sam waits.

Finally Bobby clears his throat and says, "Do you believe this guy?"

"I'm... not sure. He sounds kinda crazy, but I don't think he's dangerous."

"Alright, well call me tomorrow morning. I'll see if I can find anything."

"Okay. And Bobby?"

"Yeah?"

"He wants to help us on our case."

"Sorry Sam, you're gonna have to figure that one out yourself."

Sam exits the call and looks behind him at the blue box sitting innocently on the grass.

"It's official," he sighs. "I've gone insane."

ooo

The four of them gather in the console room. Sam and Dean stand side by side with their backs to the door, both staring at the Doctor, who has their father's journal in his hands. Amy peers over his shoulder, looking at the strange pictures and the scrawled writing, describing monsters she always thought were the stuff of nightmares and fairy tales. The dragon, the werewolf, the shapeshifter... and things she's never heard of, too. She frowns as the Doctor turns the page to "Djinn," and runs her finger over the pencil drawing of a bald man with frightening blue eyes and black wavy tattoos all over his face.

They both look up as the Doctor slowly closes the book.

"You're experts, then?" he says.

Dean nods once, but says nothing. His expression is unfathomable to Amy. He has a perfect poker face, and so does his brother.

"And you think we would get in the way." It's not a question; the Doctor knows the answer already.

He nods to himself, rubbing the cover of the thick book between his fingers, still paused on the Djinn's yellowed pages.

"Are you sure there's no way I can help you?"

Dean's expression softens a little, and Amy sees a hint of a smile. "We're used to working alone," he says shortly, gruffly, though not unkindly.

"Then it's settled." He smiles at them, then at Amy, but only she sees the mischief in his eyes.