Title: An Impossible Task (debating change. I'd be ever so grateful of ideas)

Summary: As the walls between the universes collapse, leaving everyone and everything in danger, the best of the best are drawn together. But how? And for what?

Warning: Randomness, a hell of a lot of fandoms, and spoilers for each one

Rating: T

Fandoms (may change): Harry Potter

Doctor Who

Sherlock

His Dark Materials

Pushing Daisies

The Hunger Games (possibly)

Torchwood

The Sarah-Jane Adventures

Merlin (possibly)

I'd like to apologise, in advance, for wherever this story will end up, and what will happen. I've only seen about half of series one of Merlin, a couple from series two and the last two episodes of series four, so I'm not sure if I'll include it. As for the Hunger Games, I'm not sure how I can work it in. I'm also sorry if characters are OOC in this, especially Sherlock. I suck at writing Sherlock. Another thing to apologise for; I can't seem to split this into chapters, so, Hunger Games-style, it's in parts. So here's part 1.

Disclaimer: Rights to BBC, J.K. Rowling, Philip Pullman, etc.

Part I

"Harry?"

Hermione, Ginny and Ron were all looking at him concernedly. The four of them were sitting by the black lake, staying on after the rest of the volunteers had left. The castle was looking much better now; the repairs had almost been finished. It would be reopened in time for September the 1st, as usual, as if nothing had happened.

Of course that was not the case.

The summer after the war had been a painful one. The victory against Voldemort and the Death Eaters was dampened somewhat significantly by the amount of deaths and injuries. The dead lay between countless mounds of fresh earth, and a memorial stone, carved from white marble, lay on the vast front lawn of the almost-rebuilt Hogwarts. The survivors mourned, trying to carry on.

"Are you all right?" Hermione asked. She then sighed. "No, don't answer that."

"It wasn't your fault. Any of it."

"How do you know? Fred—"

"You can't do anything about it!" Ginny cut him off. "He died laughing; that's how he would've wanted to go. Stop beating yourself up over it."

"There's so many memories here," Hermione murmured, after a lengthy silence. "Happy memories. Focus on that instead."

There was a crackle of electricity and a brief flash of light. Four heads turned. A young blonde woman had appeared out of nowhere and was standing on the grass a way away from the four onlookers, but it did not seem to be apparition – it did not cause such an environmental reaction.

"That works!" she exclaimed in surprise to herself, examining a device attached to her wrist, and deciding that it was unharmed and fully-functioning, she raised her head to investigate her surroundings.

"Hello!" she grinned, catching sight of them. "I'm Jenny. Pleased to meet you."

"Hi Jenny," said Harry, frowning slightly. "How did you … get here?"

"Someone gave me this," she explained, tapping the device on her wrist. "I didn't know what it does, but obviously it can transport me to different places …"

"I'm Hermione Granger," Hermione introduced, climbing to her feet. "This is Harry, Ron and Ginny. Might I ask where you've come from?"

"I was just travelling," said Jenny. "Then I met this man, he gave me this. I don't know why. But originally, I'm from a planet called Messaline."

"So … you're an alien?" Ron asked, eyebrows creasing together.

"Yes. I'm a time-lord."

"Wouldn't that be time-lady?"

"Maybe, I'd never given it much thought. Where am I now?"

"Earth, 1997."

"Cool!" Jenny exclaimed, grinning so that she looked like a young girl. "Do you mind if I stay with you guys, until I can find an alien invasion or how to use this thing properly?"

"Of course."

"Doctor!" shouted Amy, sounding extremely angry, as the TARDIS leaned dangerously to one side. "What the hell is going on?"

"Some sort of signal!" the Doctor called back happily. "I'm sorry! I can't do anything!"

"The stabilisers might help!" River yelled.

The TARDIS engines grinded to a halt, and everything righted itself. The four of them clambered to their feet, dishevelled but unhurt.

"What was that?" Rory asked shakily.

"I said. Signal," said the Doctor unconcernedly, pulling the scanner towards him. "It's not a distress signal … oh! We're on earth!"

"Which is a surprise, because ...?" Amy quirked an eyebrow, fixing her hair and clothes.

"It's not a surprise, I was just wondering where the signal came from. It doesn't seem anything too dangerous."

River gave a derisive snort.

"Alien invasion?"

"Oh. Yeah, I never thought of that."

"Of course you didn't," said Amy, walking around to peer at the scanner.

"Well why don't we go out there and find out what it is?"

"Good idea! Ger—"

"Don't. Just don't."

The doors were opened out, to reveal a vast expanse of apparently deserted beach. Amy stepped out first, drawing her jacket tighter around herself.

"Nice beach."

"This isn't earth!" the Doctor exclaimed suddenly.

"You just said it was," Rory muttered. "The TARDIS said it was."

River sniffed deeply. "It's a parallel universe. Do you know it?"

The Doctor nodded. "Darlig Ulv Stranden."

"Bad Wolf Bay," said a voice.

The four of them walked around to the other side of the police box. Two figures were standing there; a tall man with unruly brown hair, and a shorter blonde woman.

"The signal worked then," she remarked.

"Hello Doctor," the male said. "River."

The Doctor inclined his head. "Doctor."

"Have we met?" River frowned.

"Who are they?" Amy asked. "How do they know you? Why did you call him Doctor?"

"Biological meta-crisis," said the male stranger simply.

"Which means …?"

"In my last regeneration, I was travelling with a woman called Donna Noble –"

"You might want to mention your hand was cut off on Christmas day, first," the woman interrupted.

"Right yeah. I was able to grow a new one, because I'd just regenerated. I found it again, with a little help from a friend. Anyway, back to Donna. I was shot by a Dalek, and I regenerated enough to heal the wound, and then siphoned the rest of the energy into the hand. Then Donna touched it, and …"

He indicated the stranger, who smiled. "And you can call me John Smith. Everyone does. Saves confusion."

"Oh, I forgot. Amy, Rory, River, this is Rose. Rose, meet the Ponds."

"The Ponds?" Rose quirked an eyebrow. "Are you telling me that your name is River Pond?"

"Melody Pond," River corrected. "River Song. These are my parents."

"It's a strange life," Amy rolled her eyes. "She'd be three years old."

"What happened?" John asked, intrigued as to what had led her to the library.

"I was kidnapped," River shrugged.

"What happened to you?" Rose asked quietly, after a brief silence, eyes on the Doctor.

"Radiation," he said. "Christmas Day."

Comprehension dawned on John's face.

"You felt it?"

He nodded.

"How's your TARDIS coming along?" the Doctor asked suddenly.

"See for yourself," Rose said, tossing a yellow disc to him.

He caught it. "These are working again?"

"That's how we knew we needed you," John said. "The walls between the universes are breaking down. Again."

"I just hope it's not Daleks."

Amy thought she understood a little more his reaction against the Daleks all that time ago.

"What am I meant to do with this?" the Doctor asked, turning the device over in his hands.

"We've modified them a bit," John said. "Co-ordinates are set for back home. If you were able to get through without a problem –" Amy snorted "– you'll be able to travel in this universe."

"All right then."

The six of them entered the TARDIS, Rose gasping quietly in surprise.

"Yes, she looks different," said the Doctor, moving over to the console and attaching the dimension-cannon to the controls. "Changed just after I regenerated."

"How come it didn't change when you regenerated last time?" Rose asked curiously.

"Radiation's … a messy regeneration. I crashed."

"In my back garden," said Amy. "When I was just a kid. Spent the next twelve years of my life with an 'imaginary friend', who came back on my wedding night. Not exactly the most normal way to meet your future best friend and—"

"Amy!"

"– son in law," Amy continued, smirking. The Doctor blushed. Rose laughed. He turned his eyes on her instead. She was actually smiling, naturally.

"What?" she asked, frowning at him. "I'm happy for you!"

"Really?"

"Yes," she said, as though it were the most obvious thing in the world. "You've moved on, and so have I. Though I suppose a human version of you isn't really moving on …"

The Doctor busied himself in flipping switches and pressing buttons, eyes averted from the others.

"I thought you said that it 'wasn't like that' with any of your companions," said Amy, quirking an eyebrow. "In fact, I'm sure you said it."

"It wasn't," he said.

"So there's just an exception for blondes?"

"River isn't a companion!"

Amy rolled her eyes. "She's travelled with you. If you'd look over there you'd see that she's travelling with you now."

"Saved your life a few times, too."

"After you'd killed him," Rory muttered.

Rose laughed again, as the TARDIS landed. "Ok, if there was an award for most dysfunctional family it would have to go to you." She walked towards the doors. "And I've got a four year old brother and a father who was dead for years. Anyway," she opened the doors, "welcome to our humble abode."

She stepped out, and the others followed. They had landed in a garage, almost empty despite the ample amount of space there was. A UNIT-style jeep was parked next to the door, and something that closely resembled the make-shift TARDIS the Doctor and Idris had constructed had been positioned in the corner. It was definitely a TARDIS – the almost breathing-type sound was distinctively similar, along with the orangey glow. It was a shell-less TARDIS, just a console, with two steps leading up to it.

"It's coming on well," John said. "For three years. Haven't tried to use it yet, but …"

"Donna was right, then."

He nodded.

"Do you lot want to come in?" Rose asked, walking towards a door that obviously led to the adjoining house and fishing in her pockets for keys. "I'll make tea, we can try and figure out what's going on."

Her offer was accepted, and she opened the door. Before anyone could enter, a Labrador came bounding out, heading straight for John. He scratched its ears.

Rose watched fondly for a few seconds, before walking into her house.

The kitchen was rather small, but there was space for them all around the table. It had started to rain by the time the kettle had boiled, raindrops streaming down the window, from which the road and houses opposite could be seen.

"Mum and Dad and Tony are just up the road," Rose said. "Torchwood isn't that far away. They're trying to work out what's going on. They'd be delighted to see you lot."

"What happened last time?" Amy asked interestedly.

"It all circulated around me," John said. "There was a Dalek who could tell the future, so he got Donna to the right place at the right time, to meet the Doctor. Then, when she touched the hand, she created me. And I destroyed all the Daleks. But if all that hadn't happened, he'd have died. Just after you left him, Rose."

"I know," she said, thinking of that parallel world. "I remember."

"Heard from Martha?" John asked. The Doctor shook his head.

"You should go and visit her, Doctor," said Rose. "It'd do her good. And you."

"She wouldn't recognise me."

"Not at first, but she probably would, eventually."

"Hmm …"

They drank their tea, discussing their adventures of old and what the Doctor had been doing since he'd last been to the parallel world.

"In a nutshell, regenerated, found new companions, got married and faked his own death," River had said.

Now they were all packed into the jeep, reluctant though the Doctor was to leave the TARDIS behind, on their way to UNIT.

"How come you never told me?" Amy asked, shooting the Doctor a curious look. "I would've liked to hear about them. All of them. Tell me about Martha and Donna."

"They were magnificent!" said John, from the front, where he and Rose were sitting.

"Both from London," the Doctor added. "I met Donna first, just after I'd left here … she ended up on the TARDIS, but she didn't want to travel with me. Then I met Martha. The hospital she was working at was transported to the moon by the Judoon. They were looking for an alien – not me. Anyway, when we came back to Earth, she came with me. She helped me a lot, though I don't suppose I did her any favours by mentioning Rose all the time. In the end, her family was kidnapped by the Master – that's another time-lord. But he's dead now – and she left me. Then I met Donna again, and she travelled with me … and you heard what happened, in the end. Then I regenerated, and I met you."

"And you said you'd be back in five minutes, but it ended up being twelve years," Amy smiled weakly.

"Ha!" said Rose. "He said I'd been gone for a day when he brought me back home the first time, but I'd been gone a year."

"It was an easy mistake to make!"

"No it wasn't!"

"We're here!"

There was no rain where they had ended up. They jumped out of the jeep, walking toward the Torchwood building. They were stopped at the door by two guards, though they were, as far as anyone could tell, unarmed. Rose pulled out an ID.

"Miss Tyler," one of the guards nodded. John held out his own ID. "Mr Smith."

"This is the Doctor and three of his companions," Rose said. "VIPs."

The guards nodded, standing back, granting them access.

"Seems more like UNIT to me. Though I suppose Torchwood three is completely different to this."

"It is," Rose said.

"How do you know?"

"When you lot were doing your subwave network thing, I could see you. Wherever Jack, Gwen and Ianto were standing wasn't Torchwood. At least not as we know it."

"Who's that?" River asked suddenly.

A rather timid-looking man of medium build and closely-cropped brown hair was walking purposely towards them, clipboard in hand.

"Mr Smith, Miss Tyler," he said. "A … matter has arisen."

"What?" Rose asked. "Why are you coming to us; where's Dad?"

"Your father hasn't come in yet today," the man said. "We have apprehended an intruder."

"Oh?" John raised his thick eyebrows.

"Yes. He says his name is Mycroft Holmes …"

Amy frowned suddenly.

"But?" John prompted.

"He doesn't look anything like the photograph on his ID, and … there's no such person as Mycroft Holmes on our record."

"How did he get in, then?" Rose asked.

"It's an access-all areas pass," the man explained.

"For a man that doesn't exist."

The man nodded. "He's in the cell in the basement, if you want to question him."

"We'll do that," said John. "Thank you, Carter."

He walked away with his clipboard.

"What's wrong, Amy?" the Doctor asked.

"I think I've heard of Mycroft Holmes, that's all," she said, shaking her head slightly.

"Well you've got a lot packed into that head," said River reasonably. "Must be hard to figure out what's real and what's not."

Amy nodded slowly as they stepped into a lift. Rose pressed the button which took them down to the bottom floor – from there they'd have to take the stairs.

"Are you sure you're all right?" Rory asked concernedly. Amy smiled at him, assuring him that she was.

"D'you think he's from another universe?" River asked.

"Seems the only plausible explanation," John responded.

The basement was also guarded. It was a small, unremarkable room, filled with packed boxes, and a 'cell' at the back of it. Their intruder was locked up, sitting on one of two beds. He was a tall, lithe man, with black curls and a suit, looking extremely bored and not at all frightened. Rose and John flashed their IDs at the guards, explaining that the other four were 'VIPs', and they ventured into the cell, sitting down on the bed opposite the intruder, who looked around at them.

"You've come to interrogate me." It wasn't a question.

"Yes, we have," said Rose. "My name's Rose Tyler; my father's head of this Torchwood institute."

"What's your name?" Amy asked, in what seemed an attempt to be kindly.

"Sherlock Holmes."

"And Mycroft is …?"

"My brother, who 'occupies a minor position in the British government'," he snorted.

"We don't have a Mycroft Holmes on record," said John, leaning forward slightly. "So tell me Sherlock, what happened to you?"

"I don't know," he replied, turning his eyes on each of them in turn. He seemed to be telling the truth. "I was in bed, asleep, and then I was in the middle of London. Well, it says it's London. It looks different … I know every street. This isn't familiar. So I came here trying to find some answers. Thought Mycroft's access-all-areas pass would be my best bet."

The Doctor surveyed him interestedly, before pulling out his screwdriver and scanning Sherlock, who eyed him.

"Transmat," he concluded, putting the screwdriver back in his pocket with an odd smile.

Rose's eyebrows shot up. "A transmat can't transport someone from one universe to another."

"A powerful one then," John murmured.

"Problem is, who'd be behind a transmat this powerful?" River asked, frowning slightly.

"I just hope it's not Daleks again," Rose shuddered.

"So," Sherlock interrupted their conversation, which his lack of understanding of seemed to be irritating him. "What are you going to do with me?"

"We'll let you come with us, I suppose," said John. "Provided you help us."

Sherlock nodded, offering his hand. John shook it.

"Right!" the Doctor jumped up. "Off we go. Oh and Sherlock, I'm the Doctor and this is Amy, Rory, River and John."

Sherlock's eyebrows rose. "Doctor who?"

"Just the Doctor," said Amy, in a rather long-suffering tone. "And please don't ask him why."

Sherlock turned instead to John. "Your name's John?"

"Yes, why?"

"I've got a friend called John."

"Will he be worrying about you?" Rory asked.

Sherlock shook his head.

"Why not?" River frowned.

"He thinks I'm dead."

Amy rolled her eyes. "You and the Doctor should form an 'I faked my death and lied to my friends' club. Still, he told River and she told us. Have you got a confidant?"

"Yes."

"Will they be worrying about you?"

"Possibly."

"What's their name?" Rose asked curiously.

"Molly Hooper."

"If they're married there's going to be far too much coincidence for my liking," Amy muttered.

Sherlock snorted. "Of course we're not married. She's my friend; she helped me fake my death."

Amy couldn't help notice that his prominent cheekbones flushed slightly. She bit back a smile.

"What are we here for, anyway?" Rory asked, as they left the basement.

"We're investigating this universal collision," said John. "Thought it was time we brought in the expert."

"Who?" the Doctor asked eagerly.

"You, you daft dimbo," Rose rolled her eyes, punching him lightly on the shoulder as she passed him, leading their enlarged group to the lift and pressing the button for the fifth floor.

A woman with long brown hair in a pony-tail and glasses looked up immediately on their arrival.

"Rose! John! Good to see you; we've not made any more progress, thought you could shine some light on it for us. You're more experienced, after all …"

"Guys, this is the Doctor, Amy and Rory Pond, River Song and Sherlock Holmes. Three companions and an intruder."

"I'm not an intruder," Sherlock argued. "I'm a consulting detective; only one in the world. Well … my one."

"There is no 'consulting detective' here at all," said Rose. "So yeah, you're the only one in the world. Well done."

"Show them what we've been doing," said Rose, as John pulled out his glasses, a trait he had inherited from the time-lord part of him. The others crowded around the machines interestedly, peering at the screens of information.

"Sherlock?" Molly called through to the spare room. There was no answer.

It surprised her that he had not demanded to stay there, and that it had been her who had offered the room to him – a place to keep his head down for however long he had planned.

She felt guilty every time she saw John's face, however. Their unlikely friendship had blossomed from Sherlock's 'death'. John felt that Molly was the only one he could talk to.

"Is that weird?" he'd asked, the first time they'd met for coffee. Molly had quickly assured him that it was not, and their friendship had ensued.

She felt less guilty when she saw that he was sleeping more; his eyes were less rimmed with purple, and she was able to tell Sherlock how he was.

She rapped her knuckles lightly against the door. "Sherlock! You can't stay in bed all day! I made breakfast."

Still no answer. Cautiously, she eased the door open.

There was no one there. The bed was empty, the room silent. The window was shut tightly, but he hardly would've jumped out of it in the first place. She sighed, completely confused, backing out of the room and closing the door.

Worry began to eat at her as she sat down to her lunch alone. She made two cups of coffee. As she was pouring the extra one down the sink, a knock on the door made her jump. The mug smashed in the sink. She hurried to answer the door. Was it possible that Sherlock had sneaked out and forgotten his key?

"Hello Molly," a young man, tall, thin with floppy brown hair, dressed in a tweed suit and a bowtie stood there with a wide smile. A stranger who should most definitely not know her name.

"… hello?" she said uncertainly.

He laughed. "I'm the Doctor. I'm here to help. Pleased to meet you."

"How do you know my name?" she asked, as he shook her hand rather too enthusiastically for her liking.

"I believe you've lost a friend of yours."

"Sherlock? Is he ok?"

The Doctor smiled. "Yes. He's fine. He was just transported to a different universe. Lucky we were there, really. Would you care to come with us, Molly?"

"What?" she asked, blinking.

"Come with us?" he repeated.

"Oh … ok."

He grinned. "This way."

She stepped outside, locked her flat door and followed this strange man, wondering why on earth she trusted him.

Rose glanced over her shoulder. Sherlock had long since lost interest in the readings and predictions the monitors showed, while she herself could not make out what some of them meant. He was standing by the window, staring at the bustling streets below. To those people, Torchwood was merely a secret base, guarded heavily and essential to avoid. They didn't know about the extra-terrestrial involvement, which, of course, was for the best.

"Is there a St Bartholomew's Hospital in this London?" Sherlock asked, not taking his eyes off the street.

"There's no point in looking for her," said Rose. "She won't know you. You don't exist in this universe, and if you do, you're not the same."

Sherlock turned to look at her, a scowl crossing his face. She almost laughed. "Who mentioned anyone?"

"You told us about Molly, remember?" said Amy, without looking up, but Rose could tell she was smirking.

"I didn't say she worked at St Bart's."

Rose's eyes met Amy's, and they both promptly burst out laughing.

"We're trying to work here if you don't mind," Sandra said, quite indignantly, also looking up from the screen, her glasses hanging around her neck.

"Lighten up," said Rose. "And my father employs you, don't forget. So, what've we got? Seems to be all written in code, to me. How many universes are affected?"

"Four, as far as we can tell," said Tommy, in his all-business tone. "Including this one."

"And how long 'til it spreads to the others?" John asked, eyes still fixated on the monitor.

"A day or two? We can't be sure. It's definitely gathered momentum since it started."

"Ok, thanks."

"So what now?"

"I think we should go back to the TARDIS," said River. "We're not much good to anyone here."

"She does always take me where I need to be," the Doctor mused. "Ok; let's go."

They bid farewell to the team, piling into another lift. Rose made a quick detour to the head office, to check if her father had arrived in for work yet, assuring the others she'd use her dimension cannon to go to the house – even pulling the device out of her pocket to show them – and pointing out that the jeep was not designed to hold seven people comfortably.

And so John and River climbed into the front of the vehicle, while the Doctor, Sherlock, Amy and Rory clambered into the back.

"How is it possible for the walls between the universes to collapse?" Sherlock asked interestedly.

"The Daleks – that's a race of aliens – managed to create a 'reality bomb', as they called it. It destroyed every form of matter. The stars started to disappear, so did the walls between the universes. Everything would've been destroyed if it hadn't been for Donna and John."

"Meta-crisis, you said," Amy murmured. The Doctor nodded.

Rose was waiting for them by the TARDIS when they reached the garage.

"Anything interesting?"

She shook her head. "But Dad's still not gone into work. Maybe he's sick … or Toby is …"

She shrugged, slotting the treasured golden key that she'd kept all those years into the lock of the blue box. The door opened with a creak less discernable than it had been in her time. The party of seven stepped in.

"How do you fit everything in?" Sherlock asked.

"Chameleon circuit," said John fondly, as Rose flopped onto one of the console seats, sending it bouncing slightly on its spring. "Disguised herself as a police box."

Sherlock raised his eyebrows "'Herself'?"

Several incredulous looks were shot his way.

"Can't you feel it?" Rory asked, frowning at him.

"Hear it? Listen."

All fell silent, apart from the thrumming of the TARDIS engines, which sounded far too much like breathing to be ignored.

"We met her once when she was forced into a human body," said Amy.

"She was … a little odd."

"Crazy," Amy corrected.

"Like me!" the Doctor grinned, straightening his bowtie proudly. He turned to murmur something to the console. A lever flipped over of its own accord, sending the TARDIS into flight.

"And if we end up in danger? Again?"

"We'll figure something out!"

The impossible blue box landed with a light thud. The Doctor pulled the scanner towards him, peering at the information it showed. The others crowded in around him, trying to catch a glimpse of the screen over his shoulder.

"Earth," River read off. "Early twenty-first century. Nothing dangerous as far as I can tell."

The Doctor brought up to the screen what was going on outside. It did not seem very remarkable; a block of flats, people passing by occasionally, none of the questioning the TARDIS's sudden appearance. However, Sherlock's expression changed completely.

"What?" Amy asked, looking sideways at him.

"This is where Molly lives."

"Oh excellent!" the Doctor grinned. "What number?"

"18A, but …"

"I'll just pop in and see if she'd like to come with us; won't be long." Far too excited over just this, he practically bounced down the steps and left the TARDIS joyfully, Sherlock's complaints never being voiced.

The lift the Doctor took was remarkably pristine for one in a block of flats several stories high. On Earth, they were vandalised more often than not; he knew that. He reached the doorway – its brown paint peeling slightly around the doorknob – he was looking for and knocked on it. It was opened almost immediately by a rather short young woman, with her light-brown hair tied into a pony-tail. She looked immensely worried, possibly about the sudden disappearance of her friend.

"Hello Molly," he smiled at her.

"… hello?" she greeted hesitantly.

Sherlock drummed his fingers lightly against the raised glass surface of the floor from where he sat on the topmost of the two steps leading up to it. He had been doing so for ten minutes, Rose observed. It was driving her mad, but she did not voice this, know it would come out as an irritated, "shut up!". Nobody else said anything either. It was clear that he was anxious – he'd probably wanted to go with the Doctor to his friend's flat.

It was River who snapped, though she did not utter a word. She simply left the console room, heels clicking against the glass in almost the same rhythm as Sherlock's drumming. She seemed to know the TARDIS well – of course she did, she was the Doctor's wife. Rose was still getting used to the idea. The Doctor. Married.

She had meant it; she was happy for them. She'd seen how hard it was to find happiness in the stricken universe, especially for the Doctor, who'd lived for so long; lost so much. She wanted him to be happy; she still cared about him, even though she had John.

River couldn't be human. The thought made sense as soon as it crossed Rose's brain. She remembered the Doctor telling her, "You can spend the rest of your life with me, but I can't spend the rest of mine with you. That's the curse of the Time lords." She knew that he would do everything he could not to fall in love with a human, because of the pain.

She decided to consult John.

"Do you think she's human?"

"Hmm?" he asked.

"River. Do you think she's human? I mean, Amy and Rory are human … but …"

"No, I don't think she's human," he said. "At least not fully. Though it won't make any difference."

"How could it not make any difference?"

"She dies, Rose," John sighed. "I've seen it happen. When I – well, he – was travelling with Donna. She gave her life to save four thousand and twenty-two people, trapped on a computer hard-drive. I wanted to do it, but she knocked me out and handcuffed me so I couldn't. she said, 'It would burn out both your hearts and don't think you'd regenerate.' And, 'You don't have a chance and neither do I.' That's when I thought she must have been like me; two hearts."

"But Amy and Rory are human," Rose said finally, digesting the horror that the Doctor would never escape pain. And to have River's impending death hanging over him all the time that they were together … Rose shut her eyes tightly.

John slid his hand into hers. Her fingers tightened around his own gratefully.

"I don't know how that could've happened," he murmured, thoughtfully. "Maybe they'd spent a lot of time travelling in the TARDIS – nobody's been travelling in it through their pregnancy before. Maybe it affected River."

"Maybe."

The TARDIS door opened. As if on cue, River reappeared in the console room and Sherlock stood up. Molly (it could hardly be anyone else) stepped in first, the Doctor close behind. She looked around in awe, the common reaction, drinking in the sheer size of the place with the numerous glass staircases leading to unknown rooms and corridors. Her eyes landed on the six assembled on the platform, sitting on standing around the console. She breathed a sigh of relief, stepping tentatively toward Sherlock and hugging him. A look of surprise flashed across her face when he reciprocated. Rose caught sight of Amy's smirk.

"So, Molly Hooper," said the Doctor, walking up to the console and setting the controls. "Welcome to the TARDIS."

She also stepped towards the console, eyes sweeping over the controls. "What's that?" she asked curiously, looking up to meet his eyes.

"Time and Relative Dimension in Space."

"How do you fit everything in?"

"It's called a chameleon circuit," the Doctor explained. "The TARDIS is designed to blend in, so here it would probably be a normal red phone box. But the circuit's broken, so she's stuck as a police box. Still fits in, though."

"Can't you fix it?" Molly asked the man, whose intelligence she guessed could easily rival Sherlock. He probably wasn't the least bit fond of that.

"Probably, if I tried," the Doctor smiled.

Rose laughed.

"What now?"

"Set the controls to random, I suppose. See where we end up."

"Good idea," River pressed several buttons on the TARDIS console, insisting she was the better flier of the machine before the Doctor could even open his mouth.

"So, do you have a … family who'll be worrying about you?"

"There's my father," said Jenny, gazing out over the water of the black lake. "But he thinks I'm dead."

"How?" Ron asked, bewildered.

"I was shot, and I think I died, but I woke up after he'd left, perfectly healed. Maybe it's got something to do with my hearts."

"Your hearts?" Ginny raised her eyebrows at the plural.

"Yeah, I've got tw— hang on, can you hear that?"

The four nodded, scrambling to their feet as a blue box appeared on the grass not too far away from them. Jenny's hearts leapt as she recognised it. She'd only seen it briefly after she'd been born, but she knew that it belonged to her father.

The door opened, and a head of floppy brown hair popped out, surveying the surroundings. Catching sight of them, the man hastily withdrew again.

"Doctor, what's wrong?" several voices asked, as he shut the doors and leaned against them, trying to make sense of what he'd just seen. It couldn't be her. It just couldn't.

"It isn't Daleks, is it?" Rose asked apprehensively.

The Doctor shook his head, swallowing. "It's … it's Jenny."

Of course, the only person this had any affect on was John. He slowly stepped down from the console steps. "What?"

"I've just seen her."

"Who's Jenny?"

"My – our, I suppose – I had his face when it happened, daughter."

"I knew it!" said Amy, her triumph completely out of place. "The way you dodged around that question when I asked you. But," she frowned. "Why are you hiding from her?"

"She's dead," said John, shaking his head in confusion. "I – well you – held her in my arms and watched her die."

"She could've regenerated," said Rose reasonably.

"I wouldn't recognise her. She looks the same now as she's always done."

"Why did you never mention you had a daughter?" Rory asked.

"I only knew her for an hour or so," said the Doctor, sighing heavily. "Donna, Martha and I – the TARDIS took us to Messaline. We ended up in the middle of the war. A progenation machine, I think it was called, took a tissue sample from me and … grew Jenny from it. But she was a soldier, born in battle, programmed to kill. I … didn't accept her. Donna sort of talked me round. Made me listen to her – Jenny's – hearts. She stopped killing people. But then, after I stopped the war, a general tried to shoot me. She … she stepped in front of me, and …" he trailed off. He could almost hear the gunshot reverberating inside his head. She'd reminded him so much of himself, and the children he'd once had, now long-lost in the time-war.

"Go and talk to her," said Molly.

"Both of you," Amy chimed in. "Go on. Family reunion."

The two of them looked at each other, before nodding and leaving the TARDIS.

Lyra trudged through the snow, her pine-marten dæmon, Pantalaimon, bundled up inside her coat, which was too big for her at any rate. At sixteen, her determination was greater than ever. Her years of loneliness were her fuel to learn the ability she'd lost; to read the alethiometer. Under Dame Hannah's watchful eye, she did learn. She wasn't an expert, but she could read it.

During her studies, she'd stumbled across an old leather book in the library of the Jordan College. She found that it contained legends, at first, and then prophecies. Some of which had actually happened. And so she had read it, and came across something that said the walls between the universes would collapse, and that everyone and everything would be in danger if they did. Lyra's heart leapt, not because of the danger that was certain if this particular foretelling came to pass, but because maybe, possibly, she could see Will again.

She had not allowed herself to hope that this would happen, tried to forget Will, but always found herself sitting on that bench on Midsummer's day. Pantalaimon, for all he tried, could not do much to help her.

It had taken a lot to persuade Dame Hannah, and then the Master of Jordan, to allow her this trip to see King Iorek Byrnison. But she felt that asking him what his opinion of this prophecy was would help her. And so an äeronaut took her as far north as he could, and she walked to rest on her own, her dæmon close to her chest, her supply of food and water, alethiometer, the book and a communication device safe in the bag that was slung over her shoulder. she was to send word for another äeronaut to come for her when she was nearing the point where the last one had left her. She couldn't wait to see Iorek again. He was the only familiar face she could turn to, as Will and Dr Malone were both in a different universe, beyond her reach, and everyone else was dead.

When she reached her destination, the ice bears did not try to stop her. Perhaps they recognised her from when she'd tricked the old king into fighting Iorek and losing. Perhaps they respected her for the part she'd played in the war against the authority.

Either way, she was not stopped as she walked up to Iorek. He looked pleased to see her.

"Lyra, my child," he greeted with a low growl. "Whatever has brought you here?"

"I wanted to talk to you," Lyra said truthfully, and then she smiled, throwing her arms around the bear's neck. He did not protest. "It's good to see you, Iorek."

He inclined his head as she stood back from him. "As it is to see you."

"I found a book, at Jordan. It's about legends and prophecies. Do you believe in prophecies?"

"If they are foretold correctly," said Iorek vaguely. "Why? What is the one of which you intend to ask me about?"

"It says that the walls between the worlds will collapse."

"I see," he growled. "This is affection for the boy?"

Lyra nodded, casting her eyes toward the ground, a dim blush appearing on her cheeks.

"There is one window left open, yes?"

"Yes," she echoed.

"There's always the chance that it could rip," Iorek growled wisely. "And that the walls, as you say, between the worlds could collapse."

"Thank you, Iorek."

She stayed for dinner, and the ice bears even cooked meat especially for her. She thanked them gratefully.

Half-way through the meal, a bear, one of the guards, came lumbering towards them.

"What is it?" Iorek asked.

"The fog … like that of years ago."

The bears abandoned their dinner and ventured outside to asses the situation. The bear was right. Lyra recognised the fog.

"It seems as if your prophecy is coming true, my child."

Jenny stood where was, staring at the blue box, wondering if she should walk up and hammer on the doors. She wondered who the floppy-haired stranger had been. He seemed vaguely familiar to her, but she couldn't imagine how; she'd never met him before.

The door opened again; the man from before, with the floppy brown hair and tweed suit, followed by someone she did recognise; her father.

The sight of him coaxed a smile from her lips, but she was ever wary that he thought she was dead. The steps she took toward the two of them were tentative. When she did reach them, her eyes flickered between the two of them, searching for a reaction.

Instead she found nothing.

"Dad?" she finally asked.

He shook his head, she drew back, her eyes locking on to those of the other man. There was something in his eyes that she found familiar. And an account she'd read while researching her species came to mind; "He looked like any ordinary man, but his eyes were so impossibly old."

Apparently seeing comprehension dawn on her face, he held out his arms, just as tentatively as she had walked towards him. She didn't hesitate to hug him, and tightly, burying her face in his tweed-coated shoulder. She didn't care that he looked different. This was her father. She'd found him at last.

She released him, taking a step back, looking between the two of them again, eyes asking for an explanation.

"Human-Time lord meta-crisis," the Doctor said. "Bit of a long story. I lost my hand, in a swordfight, but I'd barely regenerated, so I was able to grow a new one. Jack – you don't know Jack – found it and used it to find me. Called it a 'Doctor detector'. Then I took the hand. Skipping on a bit, I was shot by a Dalek. I regenerated enough to heal the wound, and siphoned the rest of the energy into the hand. Donna – you do know her –"

Jenny nodded in agreement. She remembered Donna. She'd been so kind. About to ask where she was, Jenny was cut off.

"She touched it, and …"

"Ta-da!" the other man grinned, waving the hand that Jenny supposed was the one that had been cut off. "You can call me John, ok?"

"Ok," Jenny echoed, agreeing.

He seemed to sense what was going through her head, for he said, "Look, Jenny. I do have the same memories, and thoughts, most of the time. I remember you. And Martha and Donna and," his eyes darkened slightly, "General Cobb."

Jenny hugged him as well.

"Who are your friends?" the Doctor asked curiously.

"Harry Potter, Hermione Granger and Ron and Ginny Weasley. I've only just met them."

"How did you get here?"

"Well, I stole the space shuttle from Messaline originally. I wanted to travel, like you; I did. I was on earth, and some man gave me this," she took the device from her pocket and held it out. "I didn't know what it was, so I tested it out. Then I ended up here."

"Vortex manipulator," said John immediately, after he'd taken it from her and turned it over in his hands. He handed it back. "It's a mode of time-travel. Type in co-ordinates, and it'll bring you anywhere you want at any point in time, if you get the co-ordinates right. The TARDIS is better."

Jenny was certain she'd heard of or read about these two items. She racked her brain for any information she had, holding the manipulator tight in her hands so that no harm could come to it.

"Who gave it to you?" her father asked. "What did they look like?"

Jenny tried instead to recall what the man had looked like. He had been a stranger anyway. "Umm … dark hair, white teeth. Medium height, I'd say … he was wearing one of those coats from Earth's military. And a blue shirt, with braces."

"Jack," the two men said together, with light-hearted grimaces.

"So I do know him," said Jenny. "But why did he give me this? We've never even met before."

"Must be down to us to give it to him. Lovely old Paradox."

The doors of the blue box opened. A redheaded woman stood there.

"Ok," she said, in what Jenny was sure was a Scottish accent. "You've used up your reunion time. Get in here."

"Jenny, this is Amy Pond."

Amy smiled. "Pleased to meet you, Jenny. I suppose I'm kind of your family."

"What do you mean?" Jenny asked interestedly, as they stepped inside the box, the interior of which was completely disproportionate to that of the small wooden box. Jenny was not bothered by this, however. She remembered where she'd heard the word TARDIS before. Not far into her travels, she'd found herself on a planet called the library – a whole planet filled with books. She'd looked up Time lords, eager to learn about her species. She was now standing in a type 40 TARDIS. Thinking of the Time lords' telepathic power, and the connection to the TARDIS each one had. She greeted it with her mind, and felt a reaction.

"Well," Amy explained. "My daughter is your father's wife, so, technically I'm your step-grandmother. Oh God," she said, realising what she'd said. A woman with blonde ringlets took her arm and sat her down in the seat that was not occupied while the shock wore off.

"You should've seen her face when she realised she was your mother-in-law," a man with closely-cropped brown hair muttered to the Doctor.

"Right," the Doctor said instead, while the man walked over to Amy. "Everyone, this is Jenny. Jenny, this is Rory, River, Rose, Sherlock and Molly."

Various greetings filled the air. Jenny returned them with a smile.

There was a knock on the TARDIS door. Jenny opened it, knowing who it would be.

"There's some sort of fog," said Hermione, gesturing behind her, and, sure enough, the lake and castle and everything else was surrounded by a white mist. "Can we stay here until it clears?"

"How could we fit?" Ginny, who was at the rear of the group, and could not see inside the blue box, asked.

"They've got an undetectable extension charm or something," Hermione explained.

"Yeah sure. Come in," said Jenny, stepping back from the doors, frowning a little at Hermione's words. "What do you mean?"

"How else would you fit everything in?" Hermione asked matter-of-factly.

"This is a TARDIS. It's got its own cloaking device, not a – a charm."

"Oh."

"Does that mean you're a witch?" Jenny asked, rather mistrustfully. She had come across a band of witches during her time spent travelling. They had been responsible for the light scar on her neck – determined to sacrifice her for something – a festival, most likely – during the full moon on a distant planet – uninhabited, wisely, apart from the witches. She was not keen for another similar experience.

Hermione, however, smiled kindly. "Yes, I am."

She then pulled out a thin piece of wood, holding it in front of her. The tip ignited. This was not how the witches Jenny had encountered used their magic. She relaxed slightly.

As Hermione pocketed her piece of wood, Jenny introduced the four of them to the others, explaining about the fog, even though she was sure they'd been listening.

Now that they had to stay put until the fog cleared, they sat down, mainly on the glass stairs, but Rose and Amy claiming the two seats. Pictures of the fog outside were brought up on the scanner, and they waited, talking or sitting in silence.

"Has this ever happened before?" Rose asked.

Harry shook his head. "Fog's rare enough around here, never mind this much."

"Would it have anything to do with –?"

"The universes?" the Doctor finished for her. She nodded. "Yes, I think so."

"What d'you mean?" Ron asked, looking confused.

"Something happened and now you can basically hop from one universe to the other," Rose explained matter-of-factly.

"That's impossible!" said Hermione immediately.

"Normally, yes, but now, no," John muttered.

"Doctor," said Amy suddenly. She'd recovered, and was now standing in front of the scanner, eyes transfixed on the screen.

"What?" he asked, hastening to join her.

"There's something out there …"

Jenny and several others joined the pair, peering at the screen. Amy was right, there was something out there. Camouflaged perfectly by the pearly-white mist, but discernable by their eyes and … armour – Jenny shut her eyes and opened them again, but nothing had changed – were polar bears. A girl, no more than sixteen years of age, followed them, and seemed to be in conversation with the bear that plodded along beside her. But that was impossible. Bears couldn't talk.

"Looks like you were right, Rose," said River.

A few minutes later, something else emerged from the mist. Something even odder than what they'd just witnessed. Creatures, something like elephants, though with too many legs and on wheels; aliens, most likely, approached the bears and the teenage girl. The bears seemed ready to attack, but the girl cried out, and they desisted. The girl walked up to the nearest creature, and moved her arm in an odd way. It responded with its trunk.

Not long after this spectacle, the fog cleared, leaving the grounds of the castle as green and sunny as they had been before. Hermione, Ron, Ginny and Harry were the first to leave, but Jenny followed, as did the rest of the people in the TARDIS.

The girl, wearing a bulky coat, the hood of which she lowered to reveal a head of dark blonde curls, seemed grateful of human company; people who could probably tell her where she was.

She unzipped the coat, and a pine-marten climbed up to settle itself around her neck, and turned to the group of people who were watching the animal suspiciously.

"My name is Lyra Silvertongue," she introduced. "And this is my dæmon, Pantalaimon. I come from a different world."

"Your what?" Molly asked.

"Dæmon," Lyra repeated. "It's my soul, in animal form. You're the kind of people whose souls are inside your bodies, am I right?"

"You're right," said Rose.

"Who are you?" Lyra asked.

"I'm the Doctor; this is Amy, Rory, River, Rose, John, Molly, Sherlock, Harry, Ginny, Hermione, Ron and Jenny."

He said all of this very fast, but Lyra seemed to keep up with him easily enough. She smiled. "Pleased to meet you all."

"What are those things?" Amy asked.

"We are the ice bears," the bears said in union, in their deep growling voices.

"And I am King Iorek Byrnison," one of them added.

"No, I meant –"

"They're the mulefa," Lyra explained, before she could finish. "They come from a world different to mine, but I've been there before. They don't know much English; they mainly communicate using their trunks. Dr Malone can understand them. This is Atal," she indicated the mulefa she had been communicating with earlier.

"What happened?" Sherlock asked, speaking for the first time in a while.

"There was a fog, like there was a few years ago. We walked through it and ended up here … wherever here is."

"Hogwarts," said Hermione. "In England."

"Do you know why this is happening?" the Doctor asked.

"There was a prophecy that said that walls between the universes would collapse, and that everyone would be in danger when they did," Lyra said.

"Do you have it with you?" River asked.

Lyra nodded. Pantalaimon leapt from her neck to accommodate her swinging her bag from the back and pulling out an extremely old leather-bound book full of legends and prophecies. River sat down with the girl on the grass, and read the prophecy in question, though what she seemed to think she could glean from it, Jenny did not know.

The others sat down on the grassy lakeside as well. Their number had dramatically increased, if the ice bears and mulefa were included. There were about a dozen of them combined, but she couldn't be sure, as they looked so similar. Only King Iorek Byrnison was distinguishable from the rest of the bears; his armour was different, and Jenny had long since lost track of which mulefa was Atal.

"What do we do now?" Jenny asked her father.

"I don't know," he murmured, truthfully.

"I think I can help you with that," said Lyra. They looked around to see her dæmon crawl into her backpack, and return with an object, swathed in cloth, clamped securely in his teeth. He deposited this on Lyra's lap. She murmured thanks to the pine-marten, stroking its fur before she removed a round, golden object. It seemed like an over-sized pocket-watch.

"It's an alethiometer," she explained, as she opened it, tucked her hair behind her ear and twiddled with the dials. "It tells truth. What do you want to know?"

"Where do we go from here? What do we do?"

Lyra nodded, focusing her concentration on the alethiometer. A minute of two later, she spoke up. "It says that our number is too small, and two weak. And it says to you, Doctor, that you need to gather your old friends. The ones that travelled with you, that saved the universe before. The 'children of time'; the defender of the earth, the one who left, the one who forgot, the one who waited, and the others who travelled with you. It says that two of them are already here …"

"Let me see that," the Doctor said suddenly. Lyra handed to instrument over to him.

"You mightn't be able to understand it," she warned.

"Dad?" Jenny asked. He didn't answer, focusing on the object in his hand. It seemed as though he'd asked the question out loud, but he hadn't. Jenny still heard it, reverberating inside her head, Why Donna? She heard the answer too, in a strange, female voice.

She is the strongest. She has your brain, though she does not know it any longer. She must fight; she is the only hope for this universe and all others.

Jenny glanced at her father, but he still did not look her way. Instead she probed his mind gently with hers, indicating that she had heard.

He still did not acknowledge it, instead asking the alethiometer a second question. Will she die if she remembers?

And the answer. Yes.

Another apology, sorry if this is too long. Hopefully I'll have three/four parts of roughly the same length. So far I've only written two pages of the second part, though.

Let me know what you think, please =]