It wasn't until later that the idea formulated.

Sherlock had a room with Molly. Unfortunately for the both of them, it was not in the same block as where the medical students roomed- hence, Molly was considered by Sherlock not to have a permanent status as his roommate, as she took at least two nights out from "babysitting" (as Sherlock often heard her refer to her rooming situation with some of her friends with higher social-standings) Sherlock a week to stay with friends in their medical-studies haven; or, at least, somewhere where she could get tipsy and giggle until her cheeks turned salmon pink without Sherlock shooting her an annoyed look.

It was an unfortunate arrangement for Sherlock for numerous reasons, not least because Mycroft had arranged it all for him. Firstly, the medical students' room were across the square and down behind another building, meaning Molly never just popped out to get any books or anything: so when she was in for the evening, that was it. Sherlock spent an awful lot of brainpower filtering out the background noises of her listening to music, studying, or watching films with Colin Firth and Hugh Grant in. She also insisted they share the sofa of evenings, meaning Sherlock would almost invariably retire to his room, favouring sprawling out on his unmade-bed, and staring blankly up at the peeling paint.

It was also a pain because it meant Sherlock didn't have the enriching milieu of being within the camaraderie of students taking, in his opinion, worthwhile degrees. The students either side of Molly and Sherlock were studying everything from Economics to Greek. They stayed up late, perhaps surreptitiously knowing they would be lucky to get a job in a supermarket, let alone pay off any student loans, getting completely and utterly blind drunk and doing countless stupid things, often including blow-up genitalia and jelly-shots. Sherlock reckoned he'd prefer having students around who, at the very least, shared his passions for the subjects they were studying.

Also, he'd be nearer John, and wouldn't have to take walks in his coat and pyjamas late at night before an exam to see John studying by the window: second window from the top, third from the left. The way he rubbed his eyes stubbornly with the heel of his hand when he was tired, and wore sad, saggy jogging jumpers, which revealed all the right parts of his interesting corpus.

Like his beautifully-toned shoulder.

It was one of those nights where Molly was in, and was just as bored as Sherlock. She flicked channels, and browsed the internet idly, looking at pictures of cats and snorting softly every now and again, before turning to show Sherlock something wholly unamusing.

Sherlock was watching her. Feeling unusually reserved with his invariable annoyance at the world, he had taken to sitting cross-legged at the end of the sofa, with his back against the arm, watching Molly leading her pitiful life. Though, of course, his mind was elsewhere.

John played the clarinet. Sherlock was proud of the fact that he knew it- he'd dropped hints to Molly about the fact, and had questioned other blanks of students, but, as it turned out, only he, or certainly very few others, were intellectually pertained with such knowledge.

The reason Sherlock knew, was because he'd gone to the music department in the late evening, about a month after he'd started at the university. The air was bitterly cold, and he'd slipped, unnoticed, up the dark stairwell and down the corridor on the top floor in search of a storeroom, from whence he could steal a new rosin for his poor bow from whomever's case looked the most pretentious. However, he was interrupted in his mission, upon seeing a light being cast around the edge of the doorframe and out from the small window in the door opposite Practice Room A. At first, he had thought to flee, but, being a craver of perculiar facts and blackmail material (for the odd purpose), his curiosity had gotten the better of him. He remembered creeping up to the door, when suddenly, there was a softly-blown arpeggio tickling his ears. It was controlled, slightly robotic, but altogether tuneful- not to mention, obscure, being much too late for any legitimate wind-instument practices. And so Sherlock had looked through the window, careful not to cast any sudden shadows, and was unnerved to see none other than that one boy, stood in the dead-centre of the room, with a rickety music-stand and a shiny instrument.

He would have stayed longer, Sherlock reflected, had he not have been so caught aback and, though he hated to admit it, aflutter with nerves, with finding such an individual in a realm of the world he only ever visited under the cover of thick night. Since then, however, he'd tried to catch John's practices- only managing a few, thanks to the fact that he came, it seemed, when he could be bothered: so both time, location and day of the week was sporadic. Thankfully, unlike Sherlock, John liked convenience, so if Sherlock worked out which evenings John was free, he would lock all the doors on the second and third floor bar one- the one with optimum sound quality and a decent window, not to mention, the one Sherlock himself took for violin practice, when he could be bothered to leave his room.

Sherlock didn't have qualms about John. He'd observed him long enough to have learnt his fundamental nature- John was passionate about medicine, but not music. The music was something on the side, probably, Sherlock deduced, the outcome of a parental pressure of related paranoia about the state of the job market. Yet, the fact that John could read notes of the page, just as Sherlock did, and make them sound coherent, made Sherlock smile- as if it were a shared language. Which, in a sense, it was. Music was certainly a more honest language than the everyday babble of English.

As he'd played rugby, John wouldn't play that evening. He would be too tired, he expected.

Molly had become suddenly absorbed with studying. She was reading some article on a website she'd evidently run across in her quest to find as many stupid cat pictures as possible- meaning it probably wasn't credible, and Sherlock therefore didn't bother leaning forward to have a gander.

She was licking her lips as she read- changing the colour to a less intense rose, rather than the layer of candy pink overlaying it- how was that?

"I... I like what you've done on your lips. It makes them look... nicer."

Molly regarded him with an air of disbelief, blinking at him whilst answering, "Thank you... Though... Uh... It's just make-up."

There was a pause, in which a little idea popped into his head.

"What kind of make-up?"

"It's... uh... lip-gloss. Sherlock, what are you thinking about? You've got that look on your face..."

"What is it that you wear on your eyelashes?" Sherlock was stubborn and forward. Molly tried to avoid things and make ridiculous small-talk all the time with him, so he was used to ploughing through her responses for the information he needed.

"Mascara. You're not using my make-up in one of your experiments, you know... Wha-"

Sherlock sprang up from the sofa, taking Molly by surprise as he leapt over her, tattered dressing-gown fluttering out behind him like limp wings as he flew into his room, emerging moments later carrying a notepad. Molly watched him flicking through, before he found a spare page around all his messy writings and began jotting a list.

Molly turned the television off at the remote, which normally annoyed her (she liked to save power), but Sherlock didn't notice, too engrossed in his idea to stray outside of his delicate sphere of thought.

"Sheeerlooooccck..." Molly whispered, as the wind whistled a melancholy dirge in the small space between the window and the pane, across the room. Sherlock's pen skimmed almost effortlessly across the paper, as if he were commanding its speed with the full force of his terrifying and beautiful mind; the page exploding with scrawly black ink, all arrows and dots and a storm of letters, mapping his ideas. Sherlock didn't show Molly- though she did try to make sense of it all, initially from upside down, but eventually shuffling up into his personal space, and taking the fragile paper between the nook of her index finger, and her thumb.

"Skirt... Make-up..." Her eyes skimmed the list as she mumbled softly. "Bra?!" she yelped. She was ever so close, and Sherlock could feel her processing next to him. "What on earth-"

"I need your help," Sherlock deadpanned, keeping his voice a simple monotone, so to make his point crystalline.

"I-In what way, exactly?" she squeaked, still reading the list. She re-read it.

"Isn't it obvious?"

"To you, maybe."

"I need you to get me these things." Molly looked perplexed, if not a bit shocked, so Sherlock pressed on, eager to explain his point before she got any wrong ideas. He talked quickly. "I need to get closer to John, and I obviously can't do it as myself. You say he talks to rugby team members- well, I could try to join, but I'd still have the reputation I have and to be quite frank and slightly understated, sports were never really my area. So I couldn't even reinvent myself with a new identity- so, next step is, you said he hung out with girls. Talking to said girls is out as they have the combined IQ of a mountain goat and the subtlety of an elephant, and I could use you but you're too meek and wouldn't give the the intricate data I require- it needs to be a first-hand investigation. So a girl? No matter what they say nowadays, a girl will find more out about a boy if she were to grow close to him- take you and I, and Mycroft and I, as a solid example. Disguise should be easy enough, done right." He ran his hand though his short curls, losing his train of thought and staring down Molly instead, waiting for an answer.

She didn't give one. At least, not immediately. She stared dumbly at him for a good minute: though Sherlock easily read the micro-expressions brushing her facial muscles; worry, confusion, anger, reservation, angst and stubbornness. She flicked her mousy hair from her eyes, taking the list gently from Sherlock, and reading it through, slowly, one more time.

"Sherlock, this is cowardly. And idiotic."

"On the contrary, it's brilliant." There was a low hiss in his voice, like cold water against a hot pan, that Sherlock hadn't meant to make; it portrayed the point as a menacing one, rather than a mere matter-of-fact.

"No- what, can't you see? You say you don't know why you are so interested in John Watson- why not just face the truth! Even Mycroft can see it, y'know... You jerk. Knowing you, you'll succeed, but you only end up finding out exactly what I could tell you right now but instead creating this great big mess with John in the centre and all these lies and it'll destroy you," Molly looked sad, in those nice hazel eyes of hers, but she spoke without fail or pause and with scintillating deliberation in every syllable.

"No, Sherlock snarled, going to snatch back his list, but missing. "Not doing this will destroy me."

"This isn't just another puzzle! John's a person; and it's obvious why you follow him around- you like him, but God you won't admit that to yourself and-"

"Everyone is a puzzle; John is a particularly fascinating one. It has nothing to do with mere emotions."

"Jesus, Sherlock." Molly had pushed her laptop, along with the list, onto the coffee table (cratered with mug-stains and littered with scraps of paper), and now held her head in her hands, staring wearily up at him, a glint of something unfamiliar in her chesnut eyes. "You are a person. Emotions aren't weaknesses."

"Then you'll want to help me explore my supposed strengths then," Sherlock said airily, standing up and beginning to pace between the sofa and the opposite wall. Restless.

"No," Molly replied, but she was fiddling with her pyjama sleeves. She would cave, Sherlock knew that. Despite him being her junior, she admired him: and yet, he thought, as he face hardened, not enough yet to know that, as usual, this plan would work. It had to work. It always worked. He was Sherlock bloody Holmes; studying at a Russell Group university at the ripe age of 17, with a strong reputation as a genius and a psychopath, crafted in only a few months.

Molly didn't see that. Not this time, at any rate.

Sherlock came to a halt in the middle of the carpet as Molly caught his eye, and stood, transfixed in his battle of the unspoken, and boldness against the fizzling tension frissioning up his spine.

"Would you rather I went on following him round everywhere?" Sherlock enunciated, laying it down in simple, if not sympathetic terms to achieve the utmost clarity in his intentions. It wasn't about lying or anything- experiments were experiements, and he had no intention of emotionally bonding with the blue-eyed subject much. All Molly needed to do was agree to help him in his plan, the one plan that had the potential to free Sherlock's mind from its chains, and set him free from his single, painful fixation.

The thrill of an answer might keep him off heroin.

"I think you've got to find a better, less ridiculous... Oh God, it'll probably work... A plan that doesn't include you unwittingly seducing... him."

Sherlock gritted his teeth. He wasn't getting it across to her- he was a sociopathic genius, not a ditzy med-student. Their minds were wired in completely different ways.

It wasn't long before Sherlock had to escape. He didn't say anything;, just left, treading through the tension as if he were trapped in a huge basin of viscous fluid. He would sometimes wonder what it'd be like once he finished (or didn't finish) his degree, and whether he'd ever have to find a flatmate who wasn't staying because his brother had interviewed them and offered to pay half of their rent. A lifetime of tedious, menial arguments; having to hide his needles and stash in case of discovery, and having to confine experiments and violin practice to both his bedroom and social hours.

The air outside was fresh. It was sharp on his cheeks- biting with a ferocious cold that would leave the grass crying tiny, glistening beads by the early morning. He'd not bought a coat, and so remained hunched under the lobby area of the block, leaning against the wall the root for his matches and cigarettes.

The match was a beacon in the night- striking up yellow light and strange shapes in the previously black air. He watched the flame dancing for a moment at the end of the finger of wood, before holding it to the end of the ciagrette until it glowed warmly, and he gave a long, slow exhalation.

Maybe he would have to be tactful about getting Molly to assist him. Butter her up, demonstrate the lack of an alternative, and, in the meantime, learn what it what it was that John went for in a female. Trust, Sherlock supposed, if he were to get any decent information from him; though he wasn't sure if it was necessary, he would hopefully find that simple observation would be sufficient. Perhaps physical features that meant John would be more prone to open up, or at least favour his company over others.

Molly was ridiculous to think Sherlock would be able to "seduce" John. Firstly, he couldn't make it any clearer how little to do with emotions. Secondly, to avoid any escalation in such a situation, it would be as easy as pulling off a wig and declaring himself a male.

Unless some were to be believed, regarding John Watson's orientation.

Other than that, it was foolproof.