This is the M-rated version. It's nasty. If you're squeamish, there's also a T-rated version, which is not so nasty. If you're new to this story, please read chapters 1-3 in the T-rated section first.

Chapter 4

Twelve Days Earlier

Sherlock inspected himself critically in the mirror. Weatherbeaten, tanned skin, grizzled grey hair, thinning slightly on top, grey goatee (particularly horrid, but one must make sacrifices), along with British Gas anorak and ID badge, naming him as William Escott. A little putty altering the shape of his nose, and brown contact lenses, and he was certain there was no chance of recognition.

To test his hypothesis, before he called at Whittard's house, he stopped for a coffee at the internet café across the street. Taking a table near the window, he dropped a few coins from his wallet, sending them rolling across the floor. The blond-haired man at an adjacent computer bent to help pick them up, and returned them to him with a small smile.

"Thanks, mate." Faint East-end accent, gravelly from too many cigarettes.

"No problem." Not the faintest reaction. Sherlock grinned to himself. John hadn't recognised him at all. No doubt he would twig as soon as he saw the British Gas inspector knocking upon Whittard's door.

He drained his coffee whilst watching John surreptitiously. The doctor was good at surveillance, no doubt about that. He was quietly tapping away at his keyboard, and anyone glancing over his shoulder would see what appeared to be an emerging novel from the next would-be J.K. Rowling. Every now and then, he would appear to be checking the time or a text on his phone. Even Sherlock could only tell that he was taking a photograph by deducing it – the postman had called, and the phone had come up simultaneously.

Sherlock crossed the street and knocked upon the door. John's surveillance had shown that nobody was at home for the two days previously, but today, Whittard was in. The Superintendent answered.

"Morning."

"Mornin', Sir. Here to read the meter. Is this a convenient time?"

"Yeah, no problem. It's in the cupboard under the stairs, with the boiler. Bit of a mess, I'm afraid."

"That's all right, we're used to it, Sir. Yet to find Harry Potter, but everythin' else goes." Whittard chuckled politely, the children's coats hanging by the front door suggesting he would get the reference. This was going well. He was completely relaxed and unsuspicious.

Sherlock scribbled down the meter reading in his pad, then took a small gamble.

"Your pressure gauge is skipping up and down a bit. Any of your radiators need bleeding, Sir?" Almost all houses have a radiator which is temperamental, and no-one ever gets around to fixing it.

"Uh, yeah, the one in the upstairs bathroom is a bit hit and miss."

"Tell ya what, I'll sort that out for ya if ya like – 's only a five minute job, and I've got a rad key on me. I'll trade ya for a cuppa! Problem is, it can be a nightmare when the wevver gets cold and the air contracts. Makes the pressure drop, and the 'ole system can gum up. Might need to top the boiler back up wiv the fill loop after. Don't tell anyone, though, I'm not meant to do repairs when I'm meter readin', not insured, see, but I'm a fully qualified boiler engineer, and I'd feel awful leavin' ya boiler like that."

He was pleased to see the politely glazed expression on Whittard's face in response to his garrulous tech-talk, along with the genuine appreciation at this good-natured gesture. The man may be steeped in corruption, but it hadn't completely obliterated the decent, middle class streak that probably still ran through him.

"That's very kind of you. I won't say a word! Tea or coffee?"

"Tea, please. Strong, two sugars. First though, where's this bathroom?" He gestured for Whittard to lead the way, and he unconsciously obeyed. Sherlock wanted his timing to coincide with the kettle boiling. He committed the layout of the upstairs to memory as he went.

He kept up a flow of small talk as he bled the radiator (there was very little basic household maintenance he couldn't cope with; the hopeless act he sometimes put on was for convenience). Whittard seemed content enough to chat; he was getting a free service, after all.

"Right, that's sorted. I'll just check the pressure in the boiler again. That tea would come in right 'andy now."

"No problem". The superintendent disappeared off to the kitchen. Sherlock rapidly topped the boiler back up with the filling loop, then quietly stole over to the keys he had spotted in the bowl on the hall table. It was the work of seconds to take a putty impression of each of them and place the putty in a tin in his coat, before going to stand by the kitchen door.

"All up and runnin'. Should work much better now. Ah, lovely, thanks". He took the tea, and slurped it noisily – disgusting, but it was part of his role. He and his host made non-committal small talk about house prices and the congestion charge, then he handed back his mug and left, easy entry to the property in his pocket.

Sherlock had contemplated effecting his break in that night, but John had information that evening which made him reconsider.

"His kids have showed up; looks like they're staying over, and there's another girl with them; au pair or something I'd guess." He showed the consulting detective the pictures.

"Typical of his type", sniffed Sherlock. "Divorced, only gets the kids at weekends, and hires a stranger to look after them rather than spend time with them."

"So speaks the parenting expert."

"Oh, don't give me that. There's a reason I don't have kids. Anyway, you agree with me." John shrugged and grinned good-naturedly.

"Nice disguise, by the way. Never have guessed it was you. The nose was particularly good. You should take up heavy drinking."

"And spoil my good looks? Anyway, kids and an au pair in the house racks up the chances of being heard a bit too much for my liking. I think I'll wait till they're comfortably back at their Mum's. For now, there's another potential opportunity... put something nice on, we're going out." He jumped to feet, effervescent with the thrill of the chase.

"What sort of nice?" called John at the retreating back of Sherlock, disappearing into his bedroom.

"Not a tatty old jumper. The game is on, and it won't do for you to be under-dressed."

ooo-ooo-ooo-ooo-ooo-ooo-ooo-ooo-ooo-ooo-ooo-ooo-ooo

Mrs Hudson was very fond of baking. Sherlock was impressed by her scientific approach to her task, and had often basked in the warmth of her kitchen, half on his laptop, half watching her work. He had also several times been in disgrace for pinching her little culinary blow torch for his experiments – so much handier than a Bunsen.

He therefore recognised the gadget in his taller captor's hand even before it was lit, and knew what it must mean. All dignity fled at the thought of the little blue flame licking over his skin.

A grim chuckle escaped Shorter.

"I see you've guessed the next stage. Look, this isn't really our kind of thing. Makes me slightly sick to the stomach to be honest. But we're not going to stop, unless you give us what we want. And don't think we'll be too squeamish to escalate things. You'll end up begging us to kill you if you don't give us what we want. I'd personally rather let you go, let you get patched up. Nothing personal about this, see, we just want that flashdisk."

Taller lit the burner. At that moment, Sherlock couldn't have told them anything; his mind seemed frozen by the sight of that blue flame. Shorter nodded, and Taller came towards him. He threw himself frantically against his bonds, but only succeeded in hurting himself. Taller studied him impassively, like a man choosing a sandwich, or library book. He fixed on the white skin of his prisoner's ribs, under the armpit. The flame came closer, then touched. For a moment, there was no pain, then it exploded along his side. Perhaps it wouldn't be so bad if he could draw away, but the flame followed the ineffective jerks of his chest, and the pain built, as the nauseating smell of burnt flesh assailed his nostrils. He held out with only angry grunts for a few moments, then a scream escaped, then another.

The pain then subsided, and he realised with dull horror that it must have burnt through his nerve endings. That would leave a nasty scar. He could hear the sound of tearful gasps. He felt disconnected from it. His mind was fixed on the flame, and it moved away from his skin, and hovered over his chest, oscillating menacingly back and forth, as it decided where to bite next.

The back of his knee. Horrible. Worse than his chest. He was sick again, and they had to stop, as he almost choked through trying to scream at the same time. They restarted straight away, in the same spot, and an isolated part of his mind worried that the scarring would impair his walking in the future. If there was a future.

The sole of his foot. This was worse than anything so far. It took ages to burn through the thick skin, but was unbearably tender. He felt his throat crack as he shrieked. The pain stopped for a moment. His chest was heaving, the air he could pull in insufficient, red-hazed panic hammering through his ears.

"Where is the flashdisk, Sherlock?"

He told a lie, choked out wetly, snot and drool making his voice bubble as he spoke. Too obviously a lie. The punishment was applied again. And again. And again. And again. They didn't even give him a chance to speak properly; there was no way he could have coordinated a sentence, only half-pleas, half-profanities pouring from him, along with occasionally begging them to ask anybody else whose name came to mind. And again. This time, they burned his left nipple. The little black hairs around it shrivelled first, then the skin began to hiss. It would have been terrible enough to watch. To have it happen was enough to separate him from his sanity.

The torture stopped. This time, when he told them where to find the datastick, they could read the truth in his terrified eyes.

"That was the Intermediate Class", murmured Smaller. "You'd better hope we don't need to move you up a level."

They left him alone, a weeping, shivering mess, leaving the torch on the floor in front of him to remind him what to expect if they didn't get what they wanted.

ooo-ooo-ooo-ooo-ooo-ooo-ooo-ooo-ooo-ooo-ooo-ooo-ooo

Anyone feeling slightly sick now? Me too. I suppose it's got to be gruesome to be realistic. And I suppose you did choose to read the 'M' version. I want him out of there so much…. but will he get out of there in time? As always, grateful for reviews. Thanks so much for those of you who've reviewed already, and well done to the people who spotted the canon quotes.