Author's Note: This little number is set soon after A Study in Pink. John has just moved into 221b and is getting to know his flatmate, and his flatmate's amazing abilities, a little better. Remember reviews are love! Reviews for written one-shots help give birth to dreamed of, but currently unwritten, one-shots. ;-)

Vaporized

"Did you really know that Donovan was having an affair with Anderson because of her deodorant?"

"Naturally," Sherlock said without bothering to look up from the box of John's books that he was unpacking. Not that there were all that many – certainly not when weighed against the small mountains of the consulting detective's books that were littered about the flat. Mostly, John's library consisted of school texts, medical references and the odd thriller, all of which had been tidied away in a small Big Yellow storage unit along with the rest of his possessions while he was in Afghanistan. Sherlock, to his surprise, had offered to help him retrieve his few belongings when John had officially moved into the flat at 221b Baker Street. John had accepted, though he'd wondered how they'd manage to tote the larger boxes and two pieces of furniture that were definitely far too big for a taxi. He needn't have bothered worrying. At the appointed time to go and fetch his things, Sherlock had appeared with both a lorry and a man to drive it for them. Having already eaten at a handful of Westminster restaurants with Sherlock, all of them owned or managed by people the consulting detective had assisted in some fashion, John wasn't even surprised when the driver, one Benjamin Barker, proceeded to explain how Sherlock had gotten him off on a charge of tax fraud. It seemed that the agent pursuing the investigation on behalf of Inland Revenue had had salacious designs on Barker's wife. The agent was now in prison, Barker's wife was expecting their second child, and Sherlock could do no wrong in the couple's eyes. This translated into a lorry, a driver, and an extra set of hands to help move John things.

Now, only two days after moving in with Sherlock, John sat on the sitting room floor, sorting through a box of old kitchen odds and ends and wondering just how much of Sherlock's deductions was real science and how much was guess work.

"But why should the fact that they happen to use the same deodorant tell you anything? And how could you even tell?"

"My olfactory senses are extremely sensitive. What is more, I have made a study of the varying and unique odors of personal grooming products."

"Why?" he asked, watching Sherlock flip through one of his antique anatomy texts with some evidence of interest.

"The information has proven useful on more than one case."

"So, how do you know that Donovan doesn't always use the same deodorant as Carl Anderson?"

"Anderson wears Harvard Roll-On Deodorant, a scent marketed exclusively for men. Detective Sergeant Sally Donovan normally wears Camellia Antiperspirant Roll-On, from The Floral Collection. She combines this, most unfortunately, with the body spray Autograph. The scents are, I assure you, not harmonious." Sherlock looked up and met John's gaze thoughtfully. "Do you think I should tell her?"

"No," John answered hurriedly. "Definitely not."

"On the night they found Jennifer Wilson's body, Sally was not wearing either her customary deodorant or her body spray. Instead, she was wearing Harvard. Of all the people on Lestrade's MIT, only Anderson wears Harvard. Taking that together with the state of Sally's knees and my previous observations of their mating interactions, the fact that they'd spent the night together was the only conclusion that made any sense."

"Mating interactions," John echoed, startled by his new flatmate's word choice.

"Mating rituals?" Sherlock asked, looking up again.

"No, uh, mating interactions is fine."

"Hmmm," Sherlock sang. Then, tilting his head, he said, "I can't understand what Sally sees in Anderson. While she is unreasonably dismissive of my work and rather plebian in her own deductive abilities, she is not a bad investigator in comparison to her peers. Her taste in clothing, shoes and other items of personal grooming is not reprehensible. Her makeup is tasteful. Her hair strikes a balance between the feminine and the professional. Overall, she presents an appearance of quiet competence. Anderson seems out of keeping with that."

"Why do you dislike Anderson so?" John asked, rising to his feet and walking just far enough into the kitchen to drop a handful of utensils on the table. "I mean, I know I didn't see much of him, but he must be at least somewhat competent or… surely DI Lestrade wouldn't keep him on if he was incompetent? He must be a decent forensic specialist?"

"Anderson is a crime scene manager. In my opinion, and I am seldom wrong, Anderson has been promoted to the level of his own incompetence."

"That's… fairly harsh."

"It's extremely harsh, but it is not inaccurate. He should have remained a crime scene investigator. He hasn't the mental scope to oversee all the details of a forensics investigation. When he stuck to his own area of dactylography – "

"What now?"

"Fingerprint analysis. When he stuck to that, he was passable. His recent promotion, however, has left him out of his depth and utterly intractable. Why do you suppose Lestrade so often lets me see the body and the scene before he lets his own people collect evidence? He can't risk Anderson mucking things up so badly that even I won't be able to work out the pertinent details."

"Huh."

"You disagree?"

"I don't know any of the people involved well enough to agree or disagree. Besides, I'm still trying to wrap my mind around the idea that you can identify all of the toiletries used by everyone you meet… including police officers. I'm also not really clear on why it's particularly worth knowing."

"It's really not that difficult. I could tell you right now every grooming product that you've used today."

Eyebrows rising, John perched himself on the edge of his armchair and said, "Go on then."

"Are you certain?" Sherlock asked hesitantly. "People usually find it annoying when I – "

"You're stalling," John broke in, deliberately provoking. Even after only four days' acquaintance, he'd begun to pick up on the easiest ways to twit Sherlock Holmes. The man was so infallible most of the time, and could be so disdainfully superior at others, that John found it difficult to resist when he did have a chance to get his flatmate's goat.

"Fine. Going from the head downward, you use Superdrug: 2 in 1 Shampoo and Conditioner, roughly 33 pence per 100 ml. You use Simple: Pure Soap for Sensitive Skin, roughly 44 pence per 100 ml. Colgate toothpaste – I'm not certain of the exact variety as they all smell vile and largely the same – which sells for 99 pence per 100 ml. For shaving, you employ WilkinsonSword Hydro Gel Sensitive, approximately 75 pence per 100 ml. Finally, your deodorant is Woodspice for men. All of these toiletries can be purchased at Superdrug, except for the Woodspice, and all of them are the cheapest of their type available, again except for the Woodspice. Though you buy cheap grooming products, you also purchase primarily ones designed for sensitive skin, possibly because you've always had sensitive skin, but more probably because of the detrimental effect that post-traumatic stress has on the skin. From the fact that you buy such inexpensive grooming products, I could deduce one of two things. Either you simply don't like to spend money on expensive toiletries, considering it wasteful, or you can't afford to spend extra money on your toiletries. By taking into consideration the fact that you needed to find a flat share, and that your sensitive skin would probably benefit from the use of more expensive, specially formulated products, I come to the conclusion that your purchases are based more on necessity than on a moral position regarding the cost of personal grooming. The Woodspice, which is more expensive and has a scent marketed as being especially appealing to women, was most likely a gift from Harry – an attempt to help you attract a potential mate and thereby distract you from your health concerns and new civilian status."

John swallowed uncomfortably as Sherlock looked up at him expectantly. The man was terrifying in his perspicacity. "That is amazing. Absolutely amazing, but you could have simply looked in my drawer in the bath."

"But I didn't."

"No, I don't suppose you did," John said, choosing not to address the entire sensitive skin issue. PTSD-related skin problems… if Ella got wind of that… "What do you do, go up and down the aisles of Superdrug and M&S, sniffing the products?"

"Only when absolutely necessary," Sherlock admitted, wrinkling his nose in disgust. "Many of the more aggressively and cheaply scented items give me a headache. In fact…"

"What?"

"As we're going to live together, you may have to switch a few products you use to avoid offending my nose."

"Are you saying I stink?"

"Quite," Sherlock confirmed, once more examining one of John's books. John waited, and after he'd been silent for some time, Sherlock looked up questioningly. That was when the Union Jack pillow hit his new flatmate squarely on his aristocratic nose.