A/N - I don't own either Sliders or Doctor Who.

Please let me know what you think.

Parallel Worlds.

Dalek Invasion of Earth.

Wade was fed up with sliding. Not only were she and her friends now travelling at random through the different worlds ever since the timer was damaged on their first trip to that parallel world where the Russians had taken over the USA, but every time they travelled through the wormholes, their hope of returning home was plummeting faster than a stone.

Yeah, she had heard how travel expanded and broadened the mind. Wade knew that and she had seen so many things which she had never even imagined or thought to be possible. It was amazing how a simple premise like the Russians occupying America and how different Earth itself was without nuclear power, or how an oil field had been discovered underneath San Francisco (she would not think of that world where antibiotics hadn't been discovered; almost dying of a plague was the last thing she would like to think of, ever again) could result in a world which was phenomenally different from the one she and her friends knew, but travelling at random for so long only widened the gulf between their world and the one they had just arrived in.

She screamed as she was shot out of the wormhole like a cork from a bottle of champagne - why, of all the ways they could travel from world to world, did they have to go through a rollercoaster? - corkscrewing through the air until she tumbled down to the ground, and she winced in pain although she effortlessly pushed it aside as her knees and her palms scraped the concrete. Why did they keep injuring themselves like this? She kept her eyes closed while she took deep breaths to try to calm her nerves.

She heard the others tumble through the wormhole, screaming themselves as a result of the rough ride; Wade and her friends had become more than used to how rough the slide was between the worlds they'd visited, and sometimes it was rougher than on other occasions, but this one…

Wade opened her eyes, wincing as her head swam while she looked around. Pushing aside her nausea, Wade found her friends quickly. The Professor had landed on the ground and he'd been pancaked by Rembrandt and Quinn. She sighed at the sight, knowing none of her fellow travellers was going to like that. She only hoped there wasn't another pointless argument.

Sadly it looked like it was on the cards.

Maximillion groaned from underneath the others. "If you wouldn't mind," he gasped, "I would very much like to get up."

"Yeah, when I've gotten off the merry-go-round!" Rembrandt bit out, gasping.

Wade sighed and she shakily stood up, wobbling as she got to her feet; while it was occasionally fun despite the disasters they got themselves into, she really hated the pain they got into. "If this goes on, we're gonna find ourselves sent to the hospital each time we slide," she said as she paced up and down the -

Suddenly, Wade took note of their surroundings, gazing at them with confusion and horror. The wormhole had dumped them into a street, but the place was in ruins. The scene was similar to the devastation she had seen in the history books following World War 2. But there was something much worse about this. Half of the block they'd landed in looked like a giant had stomped on the street and ripped out holes out of the concrete, leaving only a few barely standing walls and shattered and burnt out windows. The holes were quite deep, with twisted pieces of piping sticking out, and she could see the holes were deep enough to crack sewers or subway lines below. Littered around the street, in various states of decay, were shattered cars. What the hell could do this kind of damage? Wade took a few steps forwards away from where they'd arrived, taking in the devastation all around them. As she stepped away from her friends, Wade took more note of their surroundings. Despite the devastation all around them, she did not recognise any of the remaining buildings or the street itself as a San Francisco street, but they were vaguely familiar even with the amount of damage caused to the place. Wade knew this was not their world; everything around them made that obvious, but then she stopped when she spotted a red double-decker bus. Curious, Wade walked over to the bus, seeing the number 22 and PUTNEY COMMON, but she now realised where they were. Wade had once visited London, a long time ago. Buses like this were famous.

"My God, what the hell happened here?" Wade turned and found the others had recovered from their trip through the slide. Like her, they were looking around the devastation in horror.

"We're not in San Francisco," she told them, deciding the mystery of the sudden move from San Francisco needed to be aired.

"What?" Quinn said.

Wade pointed to the bus and the buildings. "I think we're in London."

"But that's impossible, right?" Rembrandt looked between Wade and Quinn uncertainly. "I thought the Timer only moved us world to world, not world and space."

"No, it isn't, Mr Brown," Professor Arturo said, his expression grim as he surveyed the devastation around them. "I can definitely say this is London, but how the Timer brought us here, I can't imagine."

"It's not meant to," Quinn reassured Rembrandt without getting too technical about how the Timer worked. "I don't understand how this is possible; we should be in San Francisco."

"Speaking of the Timer, how long do we have here?" Wade asked, getting tired of the theorising; she would never understand why scientists who have no idea about something would spend so much time making theories. She might love Quinn, but she did not want him to obsess about something like that all the time.

Quinn took out the Timer. "Oh no," he whispered.

That was the last thing they wanted to hear.

"What?" Rembrandt demanded an edge in his voice Wade and the Professor both understood only too well. The Timer had been badly damaged and it had taken Maximillian and Quinn a long time to repair it to the point where the device could determine how long they had in a single world before they moved on again. Wade and the others had come to hate the Timer, but it was the only way they had of getting back to their own world. If it was damaged then they could never return home.

"There's nothing," Quinn heard the tone in Rembrandt's voice and factored it into his reply. "I don't know how long we have in this world."

Maximillian took the Timer out of Quinn's hands and he examined it for a few minutes. "It's not even damaged, and yet I can't get it to work either."

Rembrandt threw up his hands. "Terrific!"

Wade sent him a look, hoping he didn't go too far with his rant. They had arrived in a bombed-out version of London, the last thing they needed right about now was Rembrandt yelling like this. "What caused all of this devastation anyway?" She asked hoping that by changing the subject along, they could stop pointless fights and pathetic blame games.

It seemed to work.

"It reminds me of the Blitz," Maximillian observed.

"But the damage wasn't this bad, surely?" Rembrandt pointed out.

The Professor made a face and nodded. "Yes, you're quite right, Mr Brown. I was just saying it reminded me of the Blitz, but even then it never looked like this."

"Some kind of terrorist attack?" Wade suggested.

"If it was, what the hell did they hit this place with, lasers?" Rembrandt pointed out.

Quinn had just found a fairly intact shop and he split up from the rest of the group and he walked inside. It was a paper shop, or whatever the British called it. It looked like a tornado had struck the place where the shelves had been torn down and everything was scattered across the floor, but that didn't bother Quinn; he knew that in the aftermath of whatever had taken place, it would be a mad rush to grab whatever was there, or what they could sell on whatever market there was.

He didn't care about that. He could understand the theory of needing to eat whatever scrap of food was left behind in a devastating mess like the one outside, but right now he wanted answers while he tried to think of a way of making the Timer work and getting them away from here without everything going to hell.

Like it would be so easy, a treacherous part of his mind uttered, and he winced as memories of how an alternate version of himself had become Patient Zero and he was blamed for a deadly pandemic surfaced in his brain, to say nothing of how another version of himself inadvertently got him arrested. The problem was he was currently out of his depth, and he was confused by how the Timer had opened a wormhole to London when their last location was in San Francisco. He didn't understand it, the wormholes they were travelling through moved them through parallel worlds, not through time or space...

Quinn's eyes widened as he picked up a newspaper. The headline screamed INVASION OF EARTH.

Quickly he picked up the newspaper, although he had to pick it up gently when he realised it was fragile, he quickly read through the story. While he found the headline melodramatic, he saw it was accurate.

"Quinn? Quinn where are you?" He heard Wade call.

"I'm in here," he called over his shoulder, turning when he saw Wade come in, followed by the others with worried expressions on their faces. Clearly, they had been looking for him for a while, too afraid to wander off. He couldn't blame them although all of them knew better than to wander off although sometimes they were separated by unwanted circumstances.

Wade came over and looked at the newspaper and her eyes widened. "An alien invasion?"

"Yeah. I'd just started reading it when you guys came in, but I've picked up enough to know what happened," Quinn said grimly, looking down at the newspaper. "The invasion started when magnetic pulses struck down hundreds of people. Only those who survived underground, underwater, like in tunnels or in rooms walled with metal and concrete survived."

"Oh my god," Rembrandt whispered in horror.

"That's not the worst of it. When the aliens came a year later, the human race was largely destroyed. The magnetic pulses had already killed millions by that point, and because communications went down nobody knew about how to escape them," Quinn went on.

"That's a classic tactic, Mr Mallory. If an alien race saw the Earth as an attractive world to conquer they would want to weaken the planet up," Arturo commented.

The casualness in the statement made Wade turn on him in anger. "This is human lives you're talking about, Professor-!"

"I'm not disputing that, Miss Welles. Never doubt that. The fact a clearly intelligent race would attack Earth in such a manner is horrific in itself, but we have to hope humanity in this world survived," the professor fixed Quinn with a look, "what else does the newspaper say?"

"There's not much; transport and lack of communication made it hard for the newspapers to do anything but speculate about what's happening elsewhere, but here in Britain there's a bit more info. The aliens attacked Earth with waves of fighters. They attacked what was left of the military bases and they began demolishing as many of the cities as they could for landing sites. Then it just stops," Quinn waved the newspaper in his hand, "this is the only edition here."

Something had just caught Wades' eye and filled her with dread. "Quinn, hold still. I saw something on the date…"

Wade leaned in and she squinted at the date on the front page while she grasped it in her hands to get a closer look. The newspaper wasn't really in the best of conditions due to wear and tear, but as she leaned in and read, the young woman's face became set. "Quinn, you know how the Timer doesn't send us anywhere in space until now?"

"Yeah," Quinn said slowly while the others looked worried about what was coming next.

"The year on the newspaper is dated 2004."

"2004? But that's impossible; in all the worlds we've visited, it's been 1995!"

"9 years in the future?" Rembrandt looked around himself and shivered, clearly finding the new millennium to be a really unpleasant place.

"It might not be our world-."

"How the hell do we not know that? We're not even in America, we don't know the details of what's happened!" Rembrandt snapped irritably in Wade's face, wincing at the way the girl stepped back, her expression hurt but sympathetic. She knew how he felt. "Sorry, Wade."

"I know," Wade gently touched the singer's arm soothingly. "We know how you feel, but losing it is not going to help."

"Yeah, you're right. But we need to find a way of getting the Timer to work again-," Quinn began, but the Professor saw a flaw in the plan.

"That might be a problem. Don't forget, the electrical system in the United Kingdom is totally different from the one in the United States, and because of the invasion I doubt there is any electricity which could help us," he pointed out.

"So we're stuck here, in the middle of an alien invasion, aliens we know nothing about," Rembrandt whispered as the horrifying implications penetrated his mind.

"I refuse to believe that. We will find a way to get out of here," Quinn said looking firmly at all of them, "we always do…"

Wade knew that they had, but she had a horrible feeling this was going to be harder. Without electricity, without the right parts or tools, they would be hard-pressed to find a way of repairing the Timer, never mind working out what was wrong with the fucking thing….

"What's that sound?" Rembrandt asked when a strange wheezing, groaning sound like an engine filled the air.

All of the group tensed; with the world invaded by aliens, they knew they would know they would encounter aliens in a bit.

"It's coming from out there," Quinn said, stepping out cautiously in the street, looking up and down for signs of anything alien.

"Look!" The Professor pointed at something across the street, and all of the inter-dimensional travellers looked across the road in time to see a strange blue box appearing out of thin air. They had seen a lot of weird things on their travels, but they had never seen anything like this.

X

The Doctor's expression was bleak as he examined the scanner readings. Usually, he wouldn't bother, but with the TARDIS in the state she was in, he wanted to know what was out there.

"Are we gonna take a look outside, Doctor, or are we gonna leave?" Rose interrupted his work. The Doctor sighed and carried on, deftly locking the door so Rose didn't get it into her head to walk out.

"Doctor, are we gonna take a look?" Rose's voice became slightly childish, making the Doctor grind his teeth while he checked the power systems. He didn't know why Rose was suddenly so open to the idea of visiting another parallel world, but he didn't care right now. The power was still low, but there was more than enough power for them to leave. They did not want to be here. Rose just didn't get it so the Doctor didn't bother telling her. The longer they spent in a parallel world, the more dangerous it was for the TARDIS.

"No, we're not," the Doctor replied. "I took a look at the readings; out there it looks like a version of Earth has been invaded."

"What? Who did it?"

"I don't know, but I don't want to get involved," the Doctor knew the reply would be shocking enough and it also affected him. "The old girl is still too badly damaged. We need to get back to our reality, now!"

Walking around the controls he began entering the coordinates, mentally crossing his fingers, and he pulled the dematerialisation lever…and nothing happened.

The Doctor looked at the console in horror and exasperation. "Oh no!" He hit his head in frustration.

"What's wrong?"

"She's had enough," the Doctor whispered, gazing with sudden sympathy and worry as he regarded the console of his oldest friend. "She's haemorrhaged so much power. She only has a small amount left, and she's tired."

"Surely the TARDIS can't do that, can she?"

"Oh, you'd be surprised what a TARDIS can do; even if the old girl was a newer model, she would still be doing this," the Doctor ran a hand through his spiky hair, his mind racing as he tried to work out what he could do to stop this from getting any worse. Finally, he sighed. Aside from deleting rooms - he thanked his luck he had greater control than Nyssa and Tegan had after his fourth regeneration during that mess with Castrovalva - he had nothing left.

With a sigh, he walked to the console and he began deleting rooms carefully; with all the damage the TARDIS had sustained over the centuries, the last thing he wanted to do was make it worse when he didn't have anything that could repair the old girl. When he was finished the Doctor sighed and stepped away from the console, and he walked to the door before he remembered something important.

"Oh, almost forgot!" The Doctor said in realisation and he rushed back to the console.

"What?" Rose asked.

"I need to unlock the doors. And they are!" The Doctor grinned, deftly picking up the power cell he'd used. There was enough power inside it, but he hoped what he had done with the architectural configuration system would be enough to get the TARDIS out of here. If not he had something to boost it.

"So, we're going outside?" Rose asked as she leaned by the door.

"Yes," the Doctor grinned although it didn't reach his ears since there was an invasion in a parallel world going on outside, he hoped by adopting his usual manner, Rose wouldn't say anything stupid; despite his concerns about the TARDIS, he was determined to enjoy the chance of exploring somewhere new. At the same time, he was reassured by the comforting weight of the power cell.

The Doctor threw open the door.

There were four people standing outside, looking at the Doctor and Rose in shock. Behind the group was a London street that had been completely devastated.