Connor snorted. "Sounds like a hi-tech supermarket."

At once Lucy's eyes sought him out and she smiled at him, disconcertingly. He fell silent at once, averting his eyes.

"What is this place?" Nick asked, looking around. There was a set of double doors on the far wall, a stairwell just about visible through two small panes of reinforced glass, and a locked door stood in the wall behind what appeared to be the reception desk. The building's décor gave no clue as to its purpose.

Connor raised his eyebrows as he noticed the security on each of the doors. They were metal, just like the entrance door, and all had a keypad set into them. As well as that, it appeared that they could be fastened manually with heavy bolts. Just what was this place?

"This is just the boring bit," Lucy told them, watching the curious glances. "Offices and al that. All the interesting stuff is going on downstairs."

Connor began to wonder if she wasn't just a little bit manic. And Mick was just sanding there, looking as though all this was nothing out of the ordinary at all. They were both mad, then. And they had brought the team here to - to… He had no idea.

Lucy had walked over to the door to the stairs and stood, cautiously peering through the window. "Below our feet is the world's first tachyon generator." She turned to them, and grinned. "We call it TAG."

A silence met her words. Confused faces looked back at her, with one exception. Connor's expression was a mixture of confusion and something much like delight.

"Tachyon generator," he repeated, slowly. Lucy looked at him again, her eyes narrowing speculatively as she nodded.

"You know what that is?"

"Yeah," he laughed, then hesitated. "Well, sort of. I don't know how it would work or anything like that, but I know what a tachyon is meant to be…"

The red-haired woman glanced at Mick, looking strangely pleased.

"I'm sorry," Abby interjected, not sounding sorry at all, "But what is going on here?"

At once Lucy fixed her with a wide-eyed stare, but it was her accomplice, Mick, who answered. "A tachyon is a particle. A theoretical one, up until we started experimenting. They have some rather special properties. They travel faster than the speed of light, for one."

Abby frowned. "But that's impossible." She glanced around at the others. "Isn't it?"

Connor just shrugged, and Mick smiled. "It's not. Two years ago we built a tachyon detector, TAD. It registered tachyons, but more than that - it started spontaneously emitting them."

"You made particles that travel faster than light?" Nick sounded incredulous.

"Not with any degree of reliability, which is why we built TAG," Lucy answered him, quite calmly. Then she frowned. "But things got a bit out of control. The tachyons weren't meant to violate causality. But they did."

"You mean," horror and realisation were dawning in Nick's voice, "That these anomalies - they were made by your machine?"

"You call them anomalies?" She asked, not answering his question. "That's… sweet."

"What are they, then?" Stephen's voice held an edge of hostility.

"Mistakes. Breaches." Mick hesitated, not quite meeting their eyes, before he added, "Wormholes."

"Wormholes?" Nick repeated slowly. Mick nodded, perfectly serious, and Connor laughed nervously.

"Hang on," Jenny was frowning. "If your machine is making these things, why can't you just turn it off?"

"Ah." Mick looked at Lucy, saying nothing. She grimaced.

"It's not that simple."

It never was.

"What's stopping you?" Nick asked. Or he would have, if there hadn't been a sudden crash against the front door, drowning out the rest of his sentence.

Lucy turned to Mick. "Will the door hold?"

He pulled a face. "The doorframes up here aren't reinforced like the ones downstairs. It depends on what's trying to get in this time."

There was another crash, and the doorframe juddered alarmingly. Lucy and Mick looked around, quickly making a decision.

"Come on, quickly!" Lucy told them, running for the reception desk and vaulting over it. She spun the circular release on the door behind to open it, quickly stepping inside. The others followed her, Connor rolling in after bungling his leap over the desk. They were only just in time; as Lucy closed the door they caught a glimpse of something large and scaly barging its way into the foyer.

"This room has no windows. We should be safer in here," Mick said. The walls around them were lined with grey filing cabinets' the room was obviously used for storage.

"Since we're stuck in here, I think you need to tell us what's really going on." Stephen was looking at the two of them, eyebrows raised.

"Ooh, it's you with the gun," Lucy started to smile brightly at him, but Jenny cleared her throat pointedly and she looked away. "Right, yes."

"It's not just a case of switching the machine off," Mick spoke up. "If we could, we would have done it months ago."

"So what's stopping you?" asked Nick.

"We don't have the access."

"I thought the machine was yours?" Jenny asked sharply.

Lucy rubbed the back of her neck. Mick said nothing, and would not meet Jenny's gaze. There was a brief silence, and then Lucy sighed.

"We do work here, really," she said earnestly. "But… We didn't build the machine."

"But you do know how to run it?" There was a hint of desperation in Nick's voice as he looked between them.

"No," Mick admitted, his mouth a thin line. "Not strictly. We don't have the authority to turn it on or off."

"So who does?" To say that Jenny looked displeased would be something of an understatement.

"The people who do are dead," Mick said simply. "The machine caused an anomaly shortly after switch-on. Creatures came through and killed everyone in the control room." He took a breath and his voice wasn't completely steady when he added, "We're the only ones left."

"All the damage outside - that was from creatures?" Stephen gestured towards the door.

Mick nodded. "We've been in your time. You've been getting an anomaly every couple of weeks, on average. We're getting dozens every day. They're all over the country - maybe the world, I don't know. We lost contact after the first couple of days."

A shocked silence met his words, then Nick laughed humourlessly.

"So why bring us here? A bit of sightseeing - here you go, thought you might like to witness the end of the world? Or have you got something else in mind?"

"Don't be silly," Lucy frowned at him. "We need you to help us turn it off."

And she turned her head, looking straight at Connor.

"What?" he squawked. "Me?"

"Yes," Lucy said, ignoring his concern. "We can't get into the system to initiate shutdown because we don't have the codes. But you can."

"No I can't!" he protested. "I don't know anything about tachyons or particle generators. I did A-Level physics, that's it. I've got no idea how your machine works."

"Ah," said Lucy, "But you do understand the Temple algorithm. Or will do, I should say."

"What?" Connor looked deeply confused.

"Don't ask me to explain it, I'm not into computer programming," she shrugged, "But I do know that it was developed in the year 2023 by a man called Connor Temple, and our control system utilises it."

"What year is it now?" Connor asked weakly.

She smiled grimly. "2024. And I know you're from sixteen years ago so you're weirdly young and haven't written it yet, but you're the best chance we've got."

"You're telling me," Abby said slowly, "That the computers controlling this TAG all run using a program that Connor made?"

"Yes," said Lucy simply, and Abby laughed. Nick, however, looked less amused.

"Why couldn't you just hack into it before now to shut the system down?"

"That's the thing," Mick sighed. "Doctor Serowka - that's who was in charge of the project - was a bit fanatical about security. TAG had a lot of opposition, people who didn't want the machine to run. He'd seen CERN hacked into and sabotaged, he didn't want it happening to us."

"Which was why we used Temple's program," Lucy finished for him. "It's meant to be so nonsensical that it's next to impossible to hack."

"We tried and failed," Mick sighed. "We got people in, before they all got eaten. They couldn't get into it. Which is why we need you."

Connor swallowed hard. "Oh."