AN: I do apologise for this. It started off as a tiny baby plot-bunny and has quickly mutated into a fully-fledged plot-cthulhu. And as usual I have barely any idea where it's going, I just needed to get the ideas down. Also any and all OCs that may be used at any point in this fic will be red-shirts and zombie fodder with no real importance to the plot. Post-Reichenbach, alternate to season 3.

"…Bites kill ya. The fever, burns you out. But after a while you come back."

The screen flashed off.

"Oi, Sherlock, I was watching that!" John said.

"Boring."

"Well, they don't write for people like you, Sherlock." John said, turning around.

Sherlock was stood by the door covered in blood again. John looked around for the harpoon but couldn't see it.

"Oh my god, Sherlock, what have you done?!" He yelled.

"Nothing!" Sherlock snapped. His voice sounded shaken. Barely anything could startle Sherlock Holmes.

"Sherlock," John whispered. "What's going on?"

The detective opened his mouth as if to say something clever then closed it again, gesturing hopelessly. "I don't know. But I don't think you'll need to watch The Walking Dead any more, John."

John heard banging on the door downstairs and stood up slowly, walking to the window.

A group of people were clawing at the door. John opened the window with a creak and they all looked up. John staggered back.

They weren't people at all. Their eyes were clouded over and the skin hung loosely from their faces, already half decayed.

"Sherlock?"

"Yes, John?"

"There are zombies outside our flat." He said flatly.

"What an amazing deduction, John, I hadn't noticed!" Sherlock snapped, exasperated.

"Is that blood all theirs?" John said quietly.

"None of its mine, if that's what you mean. They didn't get close enough to bite me." He looked down at his shirt with a vaguely disgusted expression. "Where's Mrs Hudson?"

"She went out to get some milk. Listen, Sherlock..."

"We have to go and find her. And Molly." Sherlock interrupted. "Get your gun, John."

"How is my gun going to help against an army of zombies?!"

Sherlock shrugged slightly and John saw the glint in his eyes had dulled the same way they had before he'd jumped from the roof of St Bart's. That was a barely disguised look of defeat. "I don't know." He paused thoughtfully. "Have you seen my harpoon?"

"What?"

"I can't kill anything with a riding crop and Lestrade took my gun. Wait," he rushed over to his chair and reached underneath, producing a machete.

John gaped.

"What?"

"No-one keeps a machete under... Oh, never mind." John pulled his jacket on.

"You coming then?" Sherlock smirked at the new challenge, walking towards the door in his usual cocky way, not caring what was on the other side of the door.

Lestrade slammed the door of the doctor's office shut and leant on it. The sickening sounds the zombies made filtered through it and the thin plaster walls. The screams had stopped before they'd even got in here. They were the only ones left alive now and the building had been locked down.

Sally Donovan was stood next to the desk, shocked and speechless. "What… What happened to them?"

"I don't know!" he snapped, sliding to the floor, his head falling into his hands. "I... Don't... Know."

He did know. But he also knew it wasn't possible. Zombies? They didn't exist. Zombies in London? Only in Shaun Of The Dead.

No-one had told the ones scratching on the door that, though.

Lestrade and Donovan's phones went off simultaneously.

'Don't go near the hospitals. Too dangerous. SH' The identical text messages read.

"That isn't helping now!" Donovan yelled, slamming her fists against the desk desperately.

Lestrade didn't reply. He hadn't been trained for this. He didn't know what to do. What they did in the films he'd seen late at night between breaks in the football were all fine and good but would they even work on these things? This wasn't possible, it couldn't be.

The phones buzzed again. 'Get to Baker Street. Urgent. SH.'

Lestrade tugged at his greying hair. Too late. They'd never get out of here, they probably couldn't even get very far from the hospital before they were caught. He almost started to laugh at this ridiculous predicament until he realised how hysterical he would sound. But he couldn't help it.

Greg Lestrade wasn't supposed to die here. He was a detective inspector. He was supposed die thirty, maybe forty, years from now of old age. He was supposed to die somewhere on the streets of London, killed by some stupid murder suspect with a gun. Not eaten by zombies.

He gave up and let himself laugh.

Donovan stared at him. "Are you ok?"

"Yeah, just great. I'm locked in the office of a man who's probably been killed by now waiting to be eaten alive by zombies! I'm fine!" He said, still laughing, getting increasingly more hysterical the more he thought about it.

"Move." Donovan said, starting to push the heavy desk towards the door.

"What are you doing?"

"This'll give us a bit more time, won't it?" She shrugged. "Maybe we can think of a plan."

"Sally, I don't know if you've noticed but there are zombies outside. The living dead! Walkers! There won't be anywhere left to go to!"

"We have to try, don't we?" Donovan yelled.

Lestrade's phone started ringing. His ex-wife. Why would she be calling him? Shouldn't she be calling that bastard he'd walked in on her with?

"What?" He said harshly, his laughter suddenly ending.

"There're these things outside! I thought they were people but... Jesus, Greg, I don't know what to do! Paul went outside and... They attacked him. He's just lying there. They're eating him! Help me!"

"I'm stuck inside a bloody hospital! What do you expect me to do?!" Why would you think I'd help you anyway? he thought, silently fuming.

"I thought..."

"You thought wrong! I'm a detective inspector, not... Not Van Helsing!"

There was a crash. "Oh god Greg... They've got in. Greg, what do I do?"

Lestrade flinched, feelings he didn't know he still had bubbling into his throat.

"Hide." He managed uselessly.

There were a few more crashes then the sound of her dropping the phone. A few seconds later there was a brief but pain-filled scream and disruption crackled through as the phone was stood on.

Lestrade froze, blinking slowly.

"Are you ok, Greg?" Donovan asked again, sounding worlds away from him.

"I have a plan, Sally." He whispered, standing up and starting to move the desk from the door again.

"Ok, great. What is it?"

"I'm going to distract the ones outside. You're going to run. Find Sherlock and John. They'll probably know what to do more than me."

"Find the freak? What kind of plan is that?!"

"Got any better ideas? At least one of us might survive this way."

"There's got to be a better way than this."

"Yeah, we could both die." Lestrade pulled his jacket straight and grabbed the door handle. "Get ready to run."

Donovan tried to protest but Lestrade opened the door, pushing past the creatures and yelling for their attention before they started to chase him. Before he turned to run, he flashed Donovan one last tired smile. Donovan was frozen in place for a moment. As soon as Lestrade had turned a corner in the corridor, she started running in the opposite direction. Find the freak. Maybe he would know what to do.