He tasted sharp, like vodka and like lemon. He stepped forward, pushing John harder into the wall, forcing his head to tilt up and his jaw to open. Sherlock dragged his tongue along the side of John's, and John's head swam with the sensory overload. The scent of his skin—that expensive soap, lemongrass: earthy with a hint of spice like ginger—the alcohol on his tongue, the pressure of his lips, the strength in the grip on his shoulders, the rain sliding down his neck—

But before John could recover from the shock-induced paralysis, before his thinking had caught up enough for it to occur to him to shove the detective back, just as soon as it had begun it was over. Sherlock stepped back, regarding John carefully. And John, as much to his surprise as anyone's, sank to the ground, sitting down hard on the street.

"Are you all right?" Sherlock crouched in front of him and scrutinised his face with concern.

"Dizzy," John breathed. His head was spinning. His skin was burning. If he didn't know better he would say it was—

"It's the drug," Sherlock said, looking into his eyes. He jumped up from his crouched position and moved to sit on a crate next to him.

"What? What drug?"

Sherlock was digging in his pocket and when John looked up again he was holding out the small container he'd seen in Alexa's room.

John blinked at it. "You stole her lipstick?"

"It's drugged."

"Oh really," John said, not overly glad to know he'd been drugged.

"You'll be fine. If my theory is correct it's just a mood-elevating drug, like the kind found in nightclubs but probably milder. I would imagine the prostitutes use it to ensure their clients get the most for their money."

Leaning back against the wall, John absorbed the information with the rain.

"I've seen this before," Sherlock said, studying the container. "Women who use lip gloss to drug people. They wear a protective lining on their lips to ensure they don't receive the effects of the drug themselves. Or possibly it's triggered by a reaction with alcohol. Did it feel like she had some kind of lining on her lips?"

The spinning in John's head was being replaced by a floating sensation. "Yeah, wait, no; what?"

Sherlock rolled his eyes and checked his watch. "Full effects of the drug kicking in now. Good to know." He stood up from the crate and held out his hand.

"Sherlock," John said, blinking up at him. His heightened skin sensitivity was making the rain feel very interesting. "What was—What was that?"

Sherlock lowered his hand. "What?"

John gestured to the wall behind him and Sherlock's eyes followed. He went still, undoubtedly replaying the kiss, the same flashing images (hands, eyes, lips, tongue) that were searing John's mind.

"Why did you do that?" John demanded.

"Amy Elliot."

"What?" If John were drugged, the least Sherlock could do was to not speak in non sequiturs.

"Come with me"—Sherlock offered John his hand again—"I'll explain when I have the complete results."

Complete results. John wasn't sure he wanted to know what that meant. Not that it mattered. Figuring out what Sherlock was on about before he explained was an impossible task even when sober. In his current state John might as well try to figure out the logic behind Sherlock's sock index, for all the success he was going to have. (He'd puzzled over it in the past, and had a vague horror that it might have as much to do with thread count as it did with colour and style.)

With some resignation John took the detective's (for once ungloved) hand, feeling the warmth of his skin tingle up his arm. When he got to his feet he felt incredibly light. His skin was humming, nerves seeming to respond in double to any contact. As a doctor, John did not condone the use of recreational drugs; however, he had to admit that the current sensation was not unpleasant. His hand felt cold when Sherlock let it go.

The rain picked up and was coming down heavily by the time they reached a main road where they could catch a cab.

John couldn't help laughing. It felt good. Really good. He took off his coat and he let the thick drops soak through his shirt. When he glanced over he saw Sherlock watching him.

"If I have to be high," John said, turning his face up to the sky, "I might as well enjoy it.

Sherlock held out his hand to catch the raindrops. "Interesting."

"What?"

"My theory. Correct as usual."

"Don't you get tired of being right all the time?"

"Nope." Sherlock shrugged off his own coat. He smiled back at John and John laughed. It was a delightfully absurd night.

They were both drenched by the time a cab pulled over.

The door to the flat swung open and its residents clambered in, laughing.

"That cabbie thinks we're nutters," John breathed.

"You didn't have to tell him about your favourite raindrops."

"There are different kinds of rain," John insisted. "Some are better than others. And what about you? Telling him to hurry because there's special lip gloss to be examined?"

"Also true."

"He probably thinks we're high."

"We are high," Sherlock grinned. He walked to the table in the living room, opened his laptop and set about connecting his microscope to it. He switched on one of his chemical analysis devices. Sherlock had so much lab equipment at the flat; John was fairly sure most of it was stolen. Or at least permanently borrowed.

"I suppose you're high now too?" John asked, coming to stand next to him.

"Yep," Sherlock said.

John reached over and cupped his chin. Sherlock jumped at the touch, but he allowed John to turn his head so that he was looking up into his eyes.

"Jesus," John said, examining his pupils, "you are high." He let go of Sherlock's face and felt a lingering burn on his fingers from the contact. Some drug. No wonder sex workers found it useful. "What were you doing? Eating the lip stuff in the cab?"

"No"—Sherlock pulled the tube from his pocket and smeared a sample onto a slide—"I was kissing you."

John felt his face get hot. He noted with interest the feel of his capillaries dilating.

"Right, and by the way, remind me, you were doing that because…"

"Of Amy Elliot."

"You know I feel like we've been here before."

Sherlock adjusted the microscope. "Thought experiment: Let's say our dead men were poisoned not by the knife that gave them the scars, but by Karina's lip gloss."

John froze.

Sherlock looked up. "No, it's not in this lip gloss"—he held up the container—"it's half empty. We'd have a lot more dead bodies by now if it were poisoned."

John relaxed as his live-in scientist placed another sample into the chemical analysis device for processing.

"Let's assume all of the prostitutes at Monroe's use this lip gloss, which is mixed with"— he glanced over the results of the analysis—"what looks like a variation on the newly popular five-methoxy-di isopropyl tryptamine."

"Oh god, which one is that?" John put his hand to his brow trying to remember the most recent seminar he'd attended for GPs about the latest club drugs in London.

"I believe its enthusiasts have termed it, 'Foxy Methoxy,'" Sherlock drawled, the last two words the vocal equivalent of an eye roll. "A fad drug—it's main selling point is the enhancement of tactile sensations. It's quite prevalent at the moment; you could get it from Billy if you wanted."

"But that's not what's in here." John pointed to the lip gloss container.

"No. Far too many possible side-effects and risk factors. Monroe's doesn't want its clients coming back with health complaints. What's in here"—Sherlock tapped the tube against his palm—"is a variation on the same concept. The pharmacology has been manipulated to make the drug milder, and much safer. There's an expert chemist somewhere in the works…" Sherlock trailed off, thinking.

"So all the girls working at Monroe's are using this drugged lip gloss?"

"Let's assume."

"Interesting business technique," John muttered. If the drug enhanced sensory awareness, the clients would leave feeling like they've never had better sex. But the dose would be small enough that combined with the effects of natural sexual stimulation and alcohol the clients might not realise they had been exposed to a drug. Sober sex comparatively feels dull, and they keep coming back.

Sherlock smirked down into his microscope. "'Interesting business technique' might be the best euphemism for illicitly drugging people I've heard in a while." John scuffed his shoe on the rug, torn between pleasure at the compliment and concern that his morally bankrupt flatmate was rubbing off on him.

"Now," Sherlock continued, "say one night someone replaces Karina's lip gloss without her knowledge. Same container, same lip gloss, different drug. Not a harmless mood-elevator but a deadly, slow-acting poison. Whoever she kisses that night gets a death sentence about two weeks out."

John listened as the pieces fell into place.

"The lip gloss is then switched back at the end of the night to ensure only the pre-chosen guinea pigs are subjected to the drug. But what if someone else was exposed to the drug accidentally? Our killer had carefully planned his victims. He couldn't abide a disruption."

"Someone else?"

Sherlock leapt up from the chair and was at the wall of photographs in a few strides. He pointed to the pictures as he said their names.

"Kathleen Bauer told us that on Friday, October ninth, she brought her friend, Amy Elliot, to Monroe's to pick up her brother, Tony, and his friend, Brandon Riley. Brandon had got the drug that night and Tony hadn't."

"And Brandon kissed Amy right away," John said, catching on. Amy spent the ride home snogging his mate Brandon in the back seat, Kathleen had said. "Wow; that's incredible. How do you do that?"

Sherlock's eyes met John's for an instant before he continued. "As soon as I saw the lip gloss in Alexa's room the idea occurred to me. But it hinged on whether or not the drug could be transmitted via secondary contact. I figured the poison would be a much higher concentration than the drug, which"—he checked the results of the chemical analysis—"is true. So, if the regular drug could be transferred through a secondary kiss in the correct timespan, then the poison must also have been."

John crossed his arms. "So in order to test your hypothesis you shoved me up against a wall and kissed me."

"I didn't think you'd volunteer for the task."

"So better to not tell me about it and hold me in place."

Sherlock shrugged.

"Was the tongue necessary?" John felt his capillaries again.

"Transmission through saliva, yes," Sherlock said without looking up. He added offhandedly, "I didn't know it would make you fall over."

John gaped. "I didn't fall over. I sat down because I was dizzy from being drugged."

But Sherlock had stopped listening. His eyes were skimming over his new data.

"I can't believe I can no longer say I've never kissed a man," John said with some astonishment, half to himself.

"That's what you can't believe about tonight?" Sherlock said, looking up from the screen. He did not like his work overshadowed.

John looked back at him.

The detective relented, "Technically I kissed you, if it helps for your record keeping."

John considered. "I'm not sure it does."

"The men who died were chosen for the experiment because they were single," Sherlock continued, evidently eager to get back to his successful unravelling of the mystery. "The killer didn't plan on Brandon kissing someone directly after walking out of the club."

"It is a bit slutty," John agreed.

"What?"

"To walk out of a 'date' with a prostitute and immediately start kissing a woman you just met?"

"The subjective 'sluttiness,' or whatever you want to call it, is immaterial. The fact is that Amy received the poison through the kiss. There was meant to be no connection between the victims. The two of them then had to be gotten rid of. So, what's a good way to kill two people and make it look like an accident?"

"Car crash," John said. It was a grim topic but his head felt light and comfortable—could a head feel comfortable? He shook it and the room swam pleasantly.

"The whole operation was clearly orchestrated by powerful people with resources. They were able to arrange a stabbing, a burglary, and have a car run off the road. The only problem was that Parker's body was sent to the same funeral home as Riley and Elliot's. The killer couldn't have foreseen the coincidence. Or that the embalmer would be a fan of your blog and put the two together."

John grinned. "My blog is important."

Sherlock rolled his eyes but John noticed he was smiling. "Yes, John, it is."

"So what now?"

"Now we have a name: Sebastian Moran."

"Have you heard of him?"

"No. Which probably means we're on the right track."

"Are we going after him tonight?"

Sherlock frowned. "Tonight? No, I'll have to go to Scotland Yard tomorrow to do research."

"Then that means you're done doing genius things tonight?"

Sherlock narrowed his eyes. "I am never done doing genius things. But I suppose the motive and method of murder for all four of our victims is satisfactory for one night's work. Just proving myself right, as usual."

"Yes, you're brilliant. Now take off your shirt."

Sherlock's eyebrows jumped up. "What?"

John was already undoing the buttons on his. The wet material had suddenly become sticky and heavy and uncomfortable against his skin. "As a doctor I can't allow you to sit there in a soaking wet shirt all night."

Sherlock looked ready to protest but then seemed to reconsider, probably also realising the unpleasantness of wet fabric against the drug-induced sensitivity of his skin.

John had gotten his shirt off and he tossed it carelessly over the arm of his chair.

Sherlock peeled off his own and dropped down onto the couch to unlace his shoes. Something caught John's attention and he walked to stand in front of Sherlock, who looked up at him with questioning eyes.

"Can I—?" John asked hesitantly, eyes flicking down to the scar on Sherlock's chest. He hadn't actually seen his flatmate with his shirt off since—since the incident.

Sherlock straightened up and leaned back. John rested his knee on the edge of the couch and braced himself on the back of it. He looked closely at the scar. The surgeons had done a good job; the ring where the bullet entered his chest had healed as nicely as one can hope a bullet wound to heal. Very unlike his own, which had been done rushed at a field surgery, leaving a jagged, uneven gash on his shoulder.

John reached to touch the scar, but his eyes darted to Sherlock's face for confirmation. Sherlock was simply watching him. He didn't say no. John lightly brushed over the spot on his chest. After just over a year the scar had flattened and faded. The ring was silvery white now. He remembered when it had been gushing red. He remembered Sherlock on his back, on the floor of Magnussen's office—he blinked hard to shut out the image, but he couldn't help the surge of hatred toward his ex-wife that coursed through him. It was smooth, youthful, unblemished skin torn open, ripped apart. It had healed well but it would never heal entirely. A beautiful body forever marred by Mary, of all people. She had been the one with the gun; the one in control. She didn't have to shoot him. There was no one forcing her. There was no good reason— But she did, he circled the scar with his finger, she did.

Sherlock must have read the anger in his face because he said softly, "It's not bad. You have one too."

He put his palm over the scar on John's left shoulder. John felt the heat of his hand burn into his skin. He'd forgotten he was also shirtless, and was suddenly very aware of what their position would look like if anyone were to walk in. Thankfully it was too late for Mrs. Hudson to come up—she would have been in bed hours ago.

"And now this," Sherlock said, sliding his hand down from John's shoulder to his upper arm where Carl Reeves' bullet had grazed him.

John's eyes glanced down over Sherlock, sitting on the couch beneath him, skin still damp from his wet shirt, and John wondered, not for the first time, if there wasn't some part of him that could be attracted to his flatmate. He would be lying if he said there hadn't been the occasional dream… The memory of pulling Sherlock up against the bars of the railing (one hand handcuffed to the mad detective and the other gripping the lapel of his coat) somehow morphing so that when Sherlock ducked his head, looking at him through the metal rails and through thick lashes, instead of turning his head John pulled Sherlock harder into the bars, into a bruising kiss…

Other dreams were not based in memory, just vivid impressions: Sherlock's pale skin under his hands, Sherlock's lean, slender body beneath him, pale eyes watching him in amazement as John used his hands, his mouth, to teach the world's most genius detective about pleasure. John woke up in a sweat, with no small amount of alarm, on the mornings after those dreams. But he dismissed them. Dreams were insanity. His subconscious was confusing the amount of time he spent with his flatmate and the depth of their friendship for something more.

John's hand skimmed from the scar lightly across his chest and he heard Sherlock's breath hitch. The effect of the drug, he knew, would intensify the touch. Sherlock's chest was smooth, virtually hairless. John didn't think he had ever seen Sherlock with facial hair either. The detective was meticulous about shaving and also (John had been amused to note) just not very good at growing facial hair.

The smooth skin was undeniably appealing, but effeminacy had nothing to do with it. Sherlock's presence was unquestionably masculine: there was no mistaking his sharp angles, his lean muscles, the way he wore a suit, and his disdain for all things sentimental. His cold, harsh energy was nearly a direct opposite of the warm and pliant femininity John had experienced in the past. And yet Sherlock was more unlike a 'man' in the stereotypical image John thought of when he thought of 'men'—hairy, coarse, and rough—than any other man he knew. John knew he could never be attracted to a 'man' in the conventional sense, but Sherlock was uniquely beautiful. Flawless, alabaster skin, exquisite bone structure, delicate features, large, dazzling eyes, lips not thin but full and surprisingly soft… The kiss from the alleyway flashed in his mind and John swallowed. That kiss had been like nothing on Earth and John found he didn't have the nerve to consider what might have happened if Sherlock hadn't pulled back so abruptly, or whether John had wanted him not to.

Sherlock was as strong as any man, stronger even, sure, but he was graceful; he was antisocial, but fashionable and cultured; genius, but entirely impractical; domineering, but helpless in so many ways… John remembered the flutter of fondness in his chest the first time Sherlock had called him from the hallway: "John! What's it doing?" he had asked blinking with large eyes at their washing machine. John had to reset the machine to clear all of the buttons Sherlock had pushed. He remembered Harry's words to him at the café not so long ago. Perhaps she had had a point…

John mentally shook the thought from his head. Even if Harry was right, even if Irene Adler had been right, even if everyone they had ever encountered was right, and he was in some way attracted to Sherlock Holmes, it didn't matter. His flatmate certainly wasn't interested in him like that (possibly wasn't interested in anyone like that), and it would be a waste of energy to convince himself otherwise. Besides, he wasn't ready himself for what it would mean if—if…

He snapped his attention back to what he was doing, which, unfortunately, was touching Sherlock's bare chest. Sherlock ran his thumb over John's old wound, and John realised the ever-curious detective must be just as interested in John's scar as John was in his. John knew Sherlock had seen it from time to time when they had lived together, but never—John didn't recollect—inspected it closely or touched it. John knew his own scar well enough by now. An ugly red marring that he had accepted would never fade, tracing out to white and silver around the edges.

Scars. As a surgeon John knew something about scars. Making the mark; breaking the skin. I'm sorry this will never be whole again, he had learned quickly to forget about thinking. The surgeries were too important; the scars were necessary. What was necessary about this? he thought, tracing the circle on the chest in front of him.

It occurred to John that he and Sherlock had always been connected by scars. His own wound had brought him back to London and prevented him from being able to live anywhere but 221B, Baker Street. And now Sherlock's had brought him back again.

"You wouldn't be here if it weren't for this," Sherlock said, voice low, reading his mind the way he always could.

"I'm sorry," John said. It was his fault. He should have seen through Mary immediately. The years living with Sherlock had taught him nothing. He was an idiot.

"I'm not."

John abandoned the scar and leaned up, braced on the back of the couch, hovering above Sherlock and looking down hard into his eyes. The detective's eyes were scintillating: evidence of the ceaseless whirlwind of thoughts behind them, the constant burning energy that animated him, propelled him, allowed him to rush the air from a room merely by stepping in.

"I chose the wrong person." He hated himself for it.

"Perhaps the boring teacher wasn't so bad after all."

John grinned in surprise at the turn. He gave a short laugh in disbelief and Sherlock grinned back at him. John pushed himself up and walked off toward the stairs. "I'm going to get clothes," he said, because it sounded like the best idea at the moment.

When he came back down wearing a faded t-shirt and a pair of jogging bottoms, which felt extra cosy compared to the wet denim he'd traded for them, he found Sherlock sitting back at the table. He was wearing silk pyjama bottoms now and a silk t-shirt (ponce) and turning the lip gloss over in his hands.

"It's a nice feeling, isn't it?"

John assumed he was referring to the drug. "Erm, yeah, I would say so."

Sherlock looked up at him. "Want to do some more?"

"Oh come on," John said. "Are you serious?"

"Look at the chemical composition!" Sherlock said, waving at his laptop. John leaned in to look at it. "You're a doctor; you can see it's harmless. It's a good high with no side effects, come on."

To be fair, Sherlock was right. The chemicals that made up the drug were relatively harmless. But still; John looked at his ex-addict friend who was looking back at him with wide eyes. God he would be in an entirely different place in his life if he had ever been able to say no to those eyes. He was glad he wasn't.

"Yeah, all right."

Sherlock smiled broadly and John wished there were more things besides murder and drugs that could get him to smile that way.