John glanced at the clock.

"It's nearly eleven – if we're going to be inventive we need to work it out soon."

"Shut up, I'm thinking." And true to his word Sherlock was sitting in a chair with his fingers steepled in front of his lips, rapidly sinking into his Mind Palace.

Shaking his head, John tried to come up with a solution, wandering around the room prodding at various computer terminals and wiping his hand over the white board, but each remained stubbornly unchanged.

He was on his third circuit of the room when Sherlock suddenly leapt to his feet.

"EVP!" he exclaimed.

"WTF?" John replied, startled. Sherlock frowned at him but before he could ask the doctor continued "Don't, just tell me what EVP is."

"Electronic Voice Phenomena. It's what they call it when people believe they can hear ghosts in the background of recordings – I've never really believed in that sort of thing but..." the younger man looked slightly confused. "It's hard to be skeptical when you find yourself in the unique position of actually being dead."

John's lips twitched as he fought to keep his smile under control.

"Anyway," Sherlock continued, "this room, like all the incident rooms here is wired for sound and vision, and the tapes run day and night to prevent tampering with evidence."

Looking up to the four corners of the room John spotted the cameras, all with built in microphones.

"So they may have heard everything we've said..."

"Possible. These are monitored from the security room on what is probably a ten minute loop." He looked down at the blond doctor standing beside him. "If we can move by 'thinking' ourselves in a place, I wonder if by thinking hard we can make ourselves heard."

"Or," said John thoughtfully, "if one of us thinks hard about the other being heard and also about getting the attention of the security officer?"

"Excellent! You concentrate on that, I'll put as much thought into being heard as I can while I explain what we know." He glanced at the clock. "If your theory about midnight is right we have fifty-five minutes."

John stepped up beside his friend and stared into the camera, concentrating all his efforts on amplifying the words Sherlock spoke, and directing them at the tape, and the security office on duty.

Sherlock for his part put as much concentration as he could into being heard by the recording equipment as he dared, without losing the thread of the information he needed to pass on to Lestrade.

xXx

23.20pm Friday 31st October 2014

Sergeant Windridge picked up his cup of coffee and took a sip. He hated night security here, it was boring and pointless – after all, who would want to break into Scotland Yard? – and what's more, he had had an annoying prickle down his spine for the past five minutes, as if someone was watching him.

Turning to the screens in front of him he gave each room a perfunctory glance, and was about to look away again when the first floor incident room flashed into view and the hair on the back of his neck stood on end.

The feeling of compulsion grew stronger as his eyes took in the two figures standing directly in front of the camera, apparently talking to it.

As if on autopilot he reached out and flicked a switch that stopped the view on this screen from moving on, and as dialled Inspector Lestrade's number he couldn't take his eyes from the scene in the other room.

xXx

Shrugging on their coats Mycroft Holmes and Greg Lestrade strode purposefully through the silent halls of the Diogenes Club and out into the chilly night air.

"If Windridge is playing silly buggers I'll have him walking the beat before the week's out." Greg ground out from between gritted teeth. "Thanks for offering the use of your car."

"My pleasure, we'll get to the bottom of this mystery and then I'll take you home."

"Are you sure you want to come..."

"You heard the description of the 'intruders' – if they are masquerading as my late brother and his friend I wish to deal with them personally."

The smile never left Mycroft's face, but Greg felt the chill of his words as they sat, side by side in the back of the black car, speeding towards Victoria Street.

xXx

On arrival they bypassed the security room and hastened up to the first floor.

John's concentration broke as he heard the lift arrive, the doors gliding smoothly open.

Sherlock also heard it – he had finished explaining for the third time the evidence linking the car showroom to the rapes, and now with John was turning to face the door.

Greg and Mycroft stopped dead.

Whatever else had happened, Sherlock and John's concerted effort to be seen had paid off, and the two living souls could see – as clear as if they had never died – the two dead ones.

"D'you think they can see us?" John asked.

"I'm fairly certain of it, given the look on their faces." Sherlock smirked.

Greg and Mycroft looked at each other, then the detective held out a hand to touch John. It passed straight through.

"Don't waste time Lestrade." Sherlock raised his voice slightly, making the two men jump. "We may not have much longer."

"How...?"

"Boring."

"Stop it Sherlock." John's eyes flicked between the two men. "Look, we don't know why – didn't even know we were dead until tonight – but here we are, and Sherlock's found a link that might help you catch the rapist."

Mycroft opened his mouth to speak but John held up a hand and shook his head.

"No, listen. If you saw us on the tape you may be able to hear us. If not you could get a lip reader in – the point is, he's found the link. If I'm right we have..." he glanced at the clock. "...five minutes before we run out of time, so just listen."

Sherlock started speaking while Lestrade wrote notes. He had barely finished when, in the distance, they chimes of Big Ben struck the hour. Midnight.

With a last look at the two men John repeated, "Watch the tape."

And before the disbelieving eyes of Scotland Yard and the British Government, the detective and his blogger faded from view.

A/N Apologies for the Oliver Chamberlain moment there...I couldn't resist.
Thanks to everyone who had read, reviewed, favourite or followed this...