Inspired by the "World Savers" series by Kerr Avonsen, but my own take on the idea that Buffy could have jumped through the portal created by Dawn's blood and ended up…in the Whoniverse. The other place where this came from is that Ithink there isn't enough Eleven love in this world. Check out Kerr's stuff, though! It's great!
Continuity: Buffy has just finished "The Gift" obviously, and this is a few days after the events of "The Big Bang" for Team TARDIS.
"I can't believe you're just sitting and feeding pigeons," Amy teased Rory, putting her shopping bags down and joining him on the bench.
"It's relaxing, after that Oriental Express in Space business," he replied, experimenting with different distances to chuck bits of Folfraxian biscuits that nobody in the TARDIS liked (or, in the case of the Doctor, didn't like anymore since his new body), but the pigeons seemed to love.
Amy grabbed a whole biscuit and hurled it some ten meters away. Three pigeons immediately began squabbling over it. She laughed. "I just thought you'd had enough of sitting quietly to last anyone, anywhere."
"I prefer it to going on the fifth souvenir expedition you've done since our wedding, or to my other option of sitting in the TARDIS while it fuels up on this 'Rift energy' and listen to the Doctor arguing on the phone with someone named Gwen." He peeked in a bag. "What are you getting your mum from Cardiff, anyway? Not particularly exciting."
"She's sort of…well…she's a sudden mum, you know? I mean, after the crack ate them the only reason I knew I had parents was I knew the basic principles of being a mammal. I want to have lots of presents when we get back." She smiled that I-can't-believe-things-turned-out-so-perfect smile and took Rory's hand.
Rory had to kiss her again, both for that and for the fact that she didn't consider going back a painful inevitable, but a natural progression once they were ready to settle down.
That was when a flash of orange sliced through the air a short distance from them, and an unconscious and badly battered young woman fell in a heap on the pavement.
Buffy could hear voices before her eyes opened properly. Two British-sounding guys. So…not a Hell dimension…probably? Please?
"Is this because of the cracks?"
"Oh no, those are over and done. Just normal Rift stuff. All sorts of people and things falling through from other dimensions, or times, or planets. Poor girl."
"She's waking up!"
She was lying on a bed. Good. She didn't appear to be restrained in any way. More good. Less likely that someone wanted to make with the torture or the slavey-slave. The light was pleasant and sort of homey. The two people at her bedside looked pretty human, though there was something off about one of them.
"Hello!" said the slightly-off-but-not-bad one, who looked really young and sort of adorkable the way Oz was, if Oz had dressed like Giles, waving this thing that looked like a pen light at her. "I'm the Doctor, and this is…"
"This is the nurse who is an actual medical nurse, Doctor," said the other guy, mildly cute and in normal clothes. He made a little motion with his hand like he was telling the Doctor not to crowd him.
The Doctor almost said something, but his eyes twinkled instead. "Right! I'll go see if Amy's making the tea without accidentally bringing a troop of fungoids to life, which has happened, not with Amy but once burned twice shy…" and he sort of trotted off, closing the door behind him.
The remaining guy smiled gently. "The Doctor's not the most comforting person when you're disoriented. My name's Rory Williams. What's yours?" He reached for something out of Buffy's vision.
"Buffy Summers. Where am I?"
Rory handed her a glass of some kind of drink. "I put a rehydration tablet-thing in there. It's worked well in the past, assuming you're human."
"I am human."
"Me too. Just checking. We've run into all sorts." He helped her sit up and drink. "Now, the answer's a little complicated. We found you unconscious on the pavement. In Cardiff. Wales."
Buffy cringed. "Yeah. Right. Sorry. Ignorant American."
"As to specifics, I want to first promise that we're nice people – or at least good people – and the Doctor's one of the great heroes of the universe."
Handing the now-empty glass to him and looking him in the eye, Buffy said, "I was half-expecting ending up in some sort of Hell being run by hideous demons, so if it's anything better than that I'll be pretty much a happy camper."
Rory raised his eyebrows. "Good. Well, you will be pleased to know that you are on the TARDIS, a time-machine and spaceship that's really big but looks like a little blue box on the outside, and like myself and my wife Amy, you are a guest of the Doctor, who is, as I said, a good bloke, despite being an alien."
"Is it possible for me to go home?"
"I don't know. The Doctor offers to take us to all sorts of times and places, but never to other dimensions."
"How do you know that I'm from another dimension?"
At this the door opened, with The Doctor carrying a tea tray and a young red-head who must have been Amy following behind. "I can sense it on you, Miss, and I am afraid that I can't send you home without endangering the universe."
"But there is tea and sandwiches, on the plus side," Amy said. Huh. Scottish.
"Totally was not expecting tea and sandwiches." Then Buffy frowned. "Is there any…"
"Yes?" the Doctor asked, putting the tray on her lap and sitting cross-legged on the floor.
"My friends will think I'm dead or trapped in some awful place. Is there any way to let them know I'm okay?"
The Doctor bit his lip. "That is possible. But I'll have to get some data and work out how to do it safely first."
"What were you doing that made you fall through in the first place?" Amy asked.
Buffy did her best to tell the story without crying. The three of them made sympathetic noises and squeezed her hand at various times. The Doctor looked like this was the most interesting thing he'd heard in years.
"Doctor, you said there wasn't magic," Amy protested when Buffy had given the gist.
The Doctor held up a finger. "Not in our universe, no. The rules work differently in some of them. There was a time when it was safe for the TARDIS to journey through those walls as well as time and space, but it's not safe any more."
"What happened?" Rory asked.
The Doctor cleared his throat. "Lovely to sit and chat, but I've got maintenance things to do! Phone calls to return! Mail to open! Irresponsible immortals to track down!"
When he was gone, Buffy asked, "What's his deal?"
Amy's voice softened and her hand sought out Rory's. "The Doctor's a species called 'Time Lord.' There was a big war. They all died except him."
"Oh God, I didn't know," Rory said.
"Should have told you, sorry." She kissed him. "Don't worry. It was going to come up at some point."
"What do you guys, you know, do?" Buffy asked, digesting this information.
"Sort of the things you do, but we weren't chosen mystically or anything. The Doctor sort of picks people to save planets and timelines with so he doesn't get lonely."
"How'd he meet you?"
Amy laughed. "Crash-landed in my backyard when I was seven. Accidentally didn't come back until twelve years later."
"We all thought he was imaginary until he came back. Three times. Though the weirdest one was when he jumped out of the stripper cake at my stag do…" At this, both Amy and Rory had to hold in laughter.
That was a not-unwelcome mental image, Buffy had to say. "I gotta hear that story."
When the Doctor returned, the three humans were laughing. And talking about him. That always seemed to happen.
"And he had a fez…" Rory was saying.
"Nobody disses the fez, Rory, May It Rest in Peace." The Doctor clapped his hands together. "Buffy! I did a search through the TARDIS databanks about the parallel universes that have been documented by the Time Lords. I found one that has magic, is tremendously unstable because of a local form of predominantly evil rifts you lot call Hellmouths, and that is protected by one female per planet at a time gaining the powers of a Slayer. Sound like yours?"
Buffy nodded. "Wait, so there are Slayers on other planets too?"
"Well, it'd be a bit much to expect a young woman to be responsible for more than one planet," the Doctor said airily, like it was the most obvious thing in the world. He gripped the upper part of the doorway and swung back and forth like a child on a jungle gym.
"You're responsible for the Universe, Doctor, or at least you act like you are," Amy said quietly.
"Since you've got this Hellmouth near where your friends live," The Doctor continued, ignoring Amy, "with enough of a power boost I should be able to let you say goodbye. The two points in reality will be weak enough to send a hologram. Then I'll open it a tiny bit and let it snap shut so it doesn't do any more harm."
"When you open it a little, couldn't I slip through real quick?" Buffy asked. She wondered what she'd do with her life if there was no Hellmouth.
The Doctor dropped to the floor, nudged Rory aside, and took both Buffy's hands in his. "No human being could survive the energy that would rip through your body if you did that. You are welcome here, though, if you like, as long as you keep my rules."
Rory and Amy gave her encouraging smiles. "We can always use another world-saver," Amy said. "The TARDIS has plenty of space."
"I'm happy there turned out to be a welcoming committee over here." Buffy extracted her hands from the Doctor's grasp. "So how do I let my friends know where to meet us?"
"Is there anyone in your social circle with notable psychic powers, or that you have once shared a mindlink with? That can be strong enough to make it through the barriers."
"I've shared dreams with some of them. Willow once went into my head." Buffy bit her lip. "What kind of power boost do you need?"
The Doctor stood and cleared his throat. "Rory, Amy, I have a treat for you."
"Oh?" Amy rose as well, and put an arm around the Doctor's.
"I don't want it to involve lizard-people, please. I have a thing about that now." But Rory looked excited too.
"We're going to go visit a supernova. Right as it explodes."
Willow awoke curled in an armchair with Tara. In the pain of losing Buffy, at least she had her lover again. They would do their very best to take care of Dawn.
The former Key and now completely human child had gone into shock shortly after the battle, and she was still in the hospital because the ceremonial knives had given her an infection. She slept in the bed beside the two witches, connected to an IV.
"I had a dream," Willow whispered.
Tara's eyes snapped open. "Buffy. She's sending a message."
"Can we be sure?"
"You're better than me at most magic, but I was born with the Sight."
"I should call Xander and see…" Willow stopped. "Actually, could you call Xander and Giles, please? Spike deserves to know. I can do a spell to cast a shadow on him and keep him safe on the way."
"I'll stay with Dawn, in case she wakes up. I don't think anything could cheer her up more than knowing I'm okay."
They kissed; Willow a little shaky still – there had been no body to bury her best friend – and Willow gathered up her purse to go.
Willow got a call from Xander on the way. "Hey, Tara said you two dreamed that Buffy can send a message to us if we go to the high school?"
He choked back a sob. "That's…thank God. I was worried it was just a dream."
"What are you doing here, Red?" Spike asked the moment she entered his crypt.
"I got a message from Buffy," she said gently.
His head whipped over to her direction. "So she's alive?"
"She's in another dimension. We can talk to her, somehow, on the Hellmouth. It's a weak point between the worlds."
He put his hands over his face. "It's the day. I'd fry. Let me know what she said, luv?"
"C'mere, Spike." Willow took his hand and led him outside. "Nocturne dimuendo."
An immense shadow covered Spike, moving with him as he walked. He noticed that it covered Willow too. "Well I'll be knackered. Any chance of you making it permanent?"
"It'll only work as long as you're holding my hand and walking with me."
"Ah well. Thank you."
"You really loved her. It's not easy for someone without a soul to do that." And she gave his hand a small squeeze, which he returned.
Anya was minding the shop and refused to come. "You'll have to forgive her," Xander said as he told them. "She's terrible at goodbyes."
It was dark and dusty in the school's abandoned basement. They could feel the darkness gnawing at them. Spike stood off on his own, smoking a cigarette. Willow and Xander sat on the ground, arm in arm for comfort. Giles paced. "If this is a trick, I swear I'll…"
"It isn't," Willow reassured him. "Tara would know. She could tell when Faith was possessing Buffy."
After what seemed entirely too long a time, a figure materialized over the Hellmouth, transparent and flickery.
"Buffy!" Spike shouted.
Buffy waved. "Hi guys. I've never really done this before."
"Are you okay, Buffster? You're not in a demon dimension, right?" Xander asked.
"This dimension doesn't have demons, apparently. It's got aliens. Some are actually nice. I'm on the spaceship of one. He's helping me send the message. It won't last long."
Then she stepped to the right and vanished. A youngish-looking man in a tweed jacket and bow tie waved to them. He had a British accent. "Hello, world-saving humans. I'm the Doctor and Buffy can stay on my ship as a guest for however long she likes. We'll try to set her up somewhere nice if she wants to leave. I'm a Time Lord, but I generally travel with a couple humans – occasionally persons of other species – and we do much the same sort of thing you do, but with more travelling through space and time. I've noticed you've got a nasty dimensional tear, so as soon as Buffy's done saying her goodbyes I'm going to close it. You can stop worrying about it."
"You can do that?" Willow asked, boggled by the power that implied.
"Oh, no problem. But I'm afraid I won't be able to send Buffy back without either killing her or tearing a hole in the space-time continuum. I don't recommend any of you mess with it either. Someone I loved was trapped in a parallel dimension once. Worse things can happen."
Then Buffy returned. She was clearly crying a little. "It turned out better than how it could've, right gang?"
"Wouldn't have traded it for anything," Xander said.
"It's been an honor," Giles said.
"Know that I'm still fighting a good fight. But over here. It'll be like I'm dead there, but that's okay, because you'll know I'm doing fine here. Give my love to Dawn."
"Tara and I will take care of her," Willow said.
"We all will," Giles said.
Spike was edging closer to the Rift. "This Doctor bloke, how is he planning on closing the Hellmouth?"
Buffy stepped aside and the Doctor reappeared. "I'm going to force it open the tiniest bit, then it'll snap shut on reflex, but for good."
"Couldn't Buffy come through?"
"It would kill any human being and have drastic effects on many other species," the Doctor said. "Now stand back, because five…four…three…"
Spike switched to his game face. "I'm already dead, mate."
And then Spike leapt through the gap in the universe.