Apologies to SeaAndSky, I don't know a lot about the Axons, and the Cybermen are a bit too clique for me. I have, however chosen another 'classic' monster that more traditional Whovians will be familiar with.

Please review and tell me what you think, I haven't had a lot of feedback for this story.

Seventh Rule

Mycroft had long since decided that Sherlock had got out of the wrong side of bed. That is, if he went to bed at all. Knowing Sherlock, it was unlikely. Mycroft surveyed him as he poured over the photographs, obsessed that something was wrong with the evidence. Mycroft knew that there was something off about the whole case, but couldn't understand Sherlock's drive to solve it.

"Argh!" roared Sherlock suddenly, sweeping everything off the desk. Across the room John sighed. Sherlock strode to the door to grab his coat, muttering about 'needing to go back to the crime scene'.

The forensic team was still there when they arrived in the little back street. Scotland yard were baffled as usual, but Mycroft had to admit that they had a point here. The three victims had no marks on their bodies. They also had not been suffocated, asphyxiated, or poisoned. Even Sherlock was at a loss. In a brief moment of curiosity he scanned the scene. Nothing. For Sherlock, that was understandable, but how could he, Mycroft, get nothing?"

Sherlock had stormed back into the thick of the investigation, ignoring Anderson's cry of protest. He snapped out his magnifying glass and started examining the hand-print one more time.

"This isn't right," he announced to anyone who was listening. He turned his head. "John, Mycroft, what do you think of these?"

Stunned at being asked for his opinion, Mycroft stepped forwards to study the wall.

"Small hands with thick and stubby fingers," said Sherlock. Should suggest a smaller build, but it is obvious from the shape of the impression that the person stumbled and leant against the wall for support. The mark is higher than it should be if the person was as small as their hands suggest. Then there's the fact that there's an impression at all. Something left a hand-print in a concrete wall. They would have to be incredibly strong, even unconsciously…"

He trailed off, and then sighed.

"Of course. John, we've got another one."

"Another…" John's eyes widened. "Jesus, how bad? Worse than the Autons?"

"Not sure yet, let's see… their body build is more solid, which suggests a high gravity planet. These things are stronger and taller than humans, with more effective weapons if those bodies are anything to go by. Slight slime deposit suggests water-based creature, while the suction pads…"

He stopped in his tracks, his face turning white.

"Shit."

And now Mycroft knew that something was seriously wrong. His little brother never swore. Most of the forensics team turned to stare as Sherlock let loose a string of expletives, pulling out his phone.

"Stupid, stupid, stupid," he finished, running his hands through his hair. "But how did they get here, there must be a ship… of course. Camouflage, it could be anywhere I suppose, well, the Doc did say they were a regression… what was the number…"

"Who are you calling?" asked Mycroft suspiciously.

"This is out of our hands," said Sherlock. "You lot, leave the scene exactly where it is, do not touch anything! I'm calling in some… experts. They will want to see it for themselves."

"You're calling for help?" gasped Lestrade and Mycroft together.

"Sorry Mycroft, but this is beyond the government. Way, way beyond."

The phone bleeped, and a computer generated voice rang out.

"This is the Unified Intelligence Taskforce. Please hold the line."

"Sherlock, what are you doing?" hissed John. Sherlock met his gaze.

"Breaking rule seven."

"To speak to a member of-"

"Oh, shut up," muttered Sherlock, jamming his finger down on the 0 button.

"Hello this is UNIT how can I help?"

"Hello, now you'd be the call-girl private, right? Well, put this into your computer. Code Nine associate Sherlock Holmes calling with a possible file 4F sighting. Personnel code alpha, seven, epsilon, terms of service delta, and security rating eleven."

There was a moments silence as the girl on the other end of the phone desperately started to type, struggling to process the information.

"Security rating eleven?" she squeaked.

"You heard correct."

There were a few murmurs, then the girl squeaked again.

"I – I have orders to pass you to On High, s-sir," she stuttered. A few people raised their eyebrows at the 'sir'. Mycroft's jaw dropped. Sherlock smirked.

"Just pass me over."

There was a harsh click.

"Brigadier Raleigh speaking."

"Well you're no Alastair, but you'll do," sighed Sherlock.

"A car is being sent to your position."

"No need, I'll get a cab."

"But sir-"

"Oh, come on! You would have to be a fool not to realise that your supposedly 'top secret' headquarters is actually the Tower of London!"

"I understand that sir, but we must exercise discretion. You cannot just walk up. The car is on its way eta ten minutes."

"And if you spend too long channing to bloody Geneva I'll have your hide."

He hung up the phone on the stunned Brigadier, and grinned.

"Oh I've missed this."

"Sherlock," asked Mycroft shakily. "What is UNIT?"

"Unknown territory for you, brother," laughed Sherlock. "For me… well let's just say John isn't the only one with experience in playing soldiers…"

TBC…