I wrote this for my best friend as a Christmas present because we're epic nerds, apparently. I also uploaded this instead of revising. It's kind of dark, but that was intentional. First time writing for either Sherlock or Alex Rider so characters are probably not right. Feedback is love.

Never have you

Sherlock can remember the first time he saw the work of Yassen Gregorovitch. The first time of many; their paths cross over and over in an intricate tangle, one trying to catch the other.

It's not always Sherlock trying to catch Yassen.

The first time, before they'd ever met face to face, the police had called Sherlock in to examine a body found in a building site. He wouldn't have gone – why should he? It wasn't an interesting case – if it wasn't for the fact that the man had obviously been killed, yet had no visible reason why. He hadn't been carrying a lot of money, he wasn't influential, he had no connection with any major world governments. In addition to this, he had been killed with an almost surgical precision. This was no random killing. Someone had put time, money, and from the looks of things a highly trained contract killer into dispatching this man. That was enough to peak Sherlock's interest. And so he found himself standing in a muddy, windswept building site on a grey day in February, rainwater trickling inside his collar, and first met Yassen Gregorovitch.

He had no idea that was who it was, of course, as he hadn't seen his work before, had nothing to cross-reference it to. Instead, he catalogued – evidently someone whose work he hadn't seen before, an expert, accustomed to killing, probably a paid killer. He listed these carefully, fitting them together to form a picture of the killer. Perfectly executed, you had to admire work like that; someone like this would be hard to catch. Maybe this case would be more of a challenge than he had thought. Not a single drop of blood spilled, just a quick snap of the neck. No fingerprints on the body. Almost certainly the dead man hadn't been in the building site when he died, so they had managed to transport the body without anyone noticing. A real professional job. Something niggled inside of him. He ignored it firmly, focussed on the case in hand.

"Have you found any reason for him to be killed yet?" he asked, fixing Lestrade with his eyes. It made him uncomfortable, which made it easier to extract the truth form him if he was unwilling to give it.

"None so far. We were hoping you'd have some idea. We though it might be some kind of random killing; you get nutters that do that sometimes."

Sherlock spared a few seconds to give him a withering look. He deserved it. "Of course it wasn't random. Have you ever seen a random killing this neatly done? No, this was a contract killing, which means this man has done something to warrant the attention of someone powerful. He clearly doesn't belong on a building site, you can tell that from his clothes, and there's the wrong kind of dirt on him for him to have been killed here. He's been dead a few hours; the ground underneath him is dry so he must have been delivered here before this rain moved in. So, a contract killer paid to kill someone then leave them somewhere out of the way but still visible enough that the body would be found within a few hours. He's involved in some kind of crime, maybe espionage, and he's been killed to make a point to whoever's controlling him."

He recognised the looks on their faces. Freak.

"Right. So we're looking for a contract killer, then?"

Sherlock snorted. "You can look, but you won't find him. Look at how professional this job is! If he thought there was the slightest chance anyone could find him he'd have removed the body from sight. No, this man won't be caught so easily. What you should be doing is finding out what the victim's criminal connection is. Find who he was working for and it may be easier to find who was behind the assassination order."

Lestrade nodded. It was the kind of nod people gave when they didn't understand but wanted him to go away. "Are you done here?"

Sherlock nodded. "If you find anything worthy of note, text me." He turned and strode off through the light drizzle that clouded the air.

Keep solving crimes people want to keep unsolved is a fast way to make enemies. This is something Sherlock learned quickly, and was often forcibly reminded of. Most enemies favour kidnapping – cars with tinted windows pulling up, or men waiting inside the front door of the house. Both of these had happened to Sherlock on several occasions. You got used to it. He always wished someone would have the imagination to try something new.

His phone vibrated just as he was crossing the road. He pulled it out and looked at the message on the screen.

32 Parkland Walk, Crouch End, London N4. Anyone you bring will be shot.

He allowed himself to grin. Kidnapping by text. Finally, someone who really thought about what they were doing. Of course, he didn't have to go. But such a text could only be from the killer at the building site. And you had to admire someone who could kill that cleanly.

Sherlock turned right, away from Baker's Street, toward the derelict warehouses in Crouch End.

32 was easy to find. Big, old, empty. Some of the windows had been smashed, but I hadn't had many to start with. The big double doors were chained shut, but a smaller side door was open just a crack. The lock had been picked, Sherlock could tell at a glance. Neatly, though – practised hands. He pushed the door open and stepped into the musty gloom. The bottom floor of the warehouse was clearly empty, part form low piles of junk. There were stairs ahead, leading up to a sort of mezzanine with offices and a walkway overlooking the space below.

There was a dark figure leaning on the railing, looking down at him. Sherlock could make out the silhouette of a gun in his hand. He didn't point it at him, but the meaning was obvious. Try anything, and I will shoot you.

"I presume you are responsible for the body discovered in the building site this morning?" Sherlock stepped towards the stairs. The man above him shifted slightly to follow his progress, keeping him in full view.

"You are correct. You are Sherlock Holmes." It wasn't a question.

"Evidently, seeing as you texted my phone and I am the one who answered." He was up the stairs now, on the same level as the other man. He has pale skin and light blond hair, cut close to his skin. Sherlock swept his eyes across him, gathering information.

"Of course. It seems the rumours about you are true, then."

"What rumours?"

The pale man laughed, a single sharp exhalation. "That you value your pride above your safety."

"Safety doesn't catch killers."

"Neither do you, in this case."

"Are you sure?"

Wrong move. The assassin moved like oil, like a striking snake, pushing off from the railing and catching his wrists together with one hand while the other forced the gun up under his chin. "You should know better than to goad people like me."

Sherlock shrugged as best he could. "I don't think you'd shoot me. Not now. After all, where's the challenge?"

He could feel the smile on the assassin's lips. "You make a mistake, Mr. Holmes, if you assume that everyone enjoys the challenge as much as you."

Sherlock turned as far as possible, and could just see one of the assassin's eyes. "Yes, but I think you do. Such a professional man as yourself can't possibly be content just shooting someone, not when they can kill so expertly as I've already seen from the unfortunate man in the building site."

The gun moved away from his throat, and his wrists were released. He turned.

"Maybe so. You are a brave man to gamble your life on it, though."

"You're a brave man to expose yourself to discovery like this."

The assassin laughed properly this time, tucking the gun back into the holster hooked over the waistband of his trousers. "If it were anyone else in this room, yes. But not you. You wouldn't turn me in, not when you know that's the easy way out."

"The easy way out?" Despite himself, he stepped forwards. Laughing like that, standing in a dusty pool of light from outside, the man was… magnetic.

"Certainly. Where is the challenge in capturing someone who tells you where they are? And if you bring me in now, you'll never know why I killed him, or on whose orders."

A phone rang, sharp and loud. The assassin pulled it out of his pocket and read the display quickly.

"Time for me to be going. Remember, Sherlock, you are not alone in enjoying the challenge."

Why did hearing his name on those lips twist something inside him?

The assassin strode down the steps, and paused just before opening the little side door. "The next time someone dies for no reason, remember Yassen Gregorovitch."

With that, he was gone. Sherlock leaned on the railing and wondered why his hands were shaking so much.

The second time Yassen and Sherlock's paths crossed, Sherlock was fleeing for his life. He'd questioned in the wrong area a little too closely. In the shadier parts of London, no one stopped to help you out. Certainly no one grabbed you by the collar and hauled you into empty, condemned houses. It took him a second to sweep the room he was in.

"You!"

Yassen smiled, a cold curling of lips. "Yes, me. Don't say thank you, really."

Sherlock catalogued the changes in him. Not many. His hair was darker, brown this time, but those icy eyes remained, as did the pale skin. Beneath his flawless English there was the slightest thickening of an accent, but it was too faint to determine where from.

"I – thank you – why did you do that?" That was another thing he didn't expect. Tripping over his words. Why would he be doing that?

Yassen shrugged, all easy grace and deliberate movement. "Because they don't deserve the prize of being the ones to finally end the infamous Sherlock Holmes. And it will teach them to keep better tabs on their target."

Sherlock stashed this information carefully. It didn't help. All the information he picked up from Yassen just confused the picture of him more and more. Contract killer, lifesaver, ruthless, clever… all he had was a list that didn't fit.

"Who are you?" he asked, not completely intentionally. Yassen laughed, although he didn't sound happy.

"You don't know? The great Sherlock Holmes doesn't know. Surely asking is too easy for you?"

Sherlock didn't reply.

"My name is Yassen Gregorovitch. Before I answer your question, I'd be interested to hear what you already have deduced about me. You've have plenty of time, after all."

"You're a contract killer. Highly paid, from the looks of your clothes and the quality of your work. You're not English, although the exact origin of your accent is escaping me. At a guess, I'd say likely Eastern Europe or the former Soviet states. You've been in the assassination business for a long time. You enjoy the challenge of killing and escaping. You do not enjoy death purely for its own sake."

"What made you think that?" Sherlock didn't like the amused look on Yassen's face as he said it.

"If you did, you'd have let those two thugs kill me."

Yassen inclined his head, acknowledging this. "Is that all you have?"

Sherlock nodded, cursing himself silently for not getting a better fix on the man.

"Impressive. Very impressive, seeing as people have managed to find a lot less even with the intelligence databases of the world at their fingertips." He settled back against the torn-up counter of the derelict kitchen they were standing in. "Right on all counts, by the way. Originally, I come from Russia. I am considered on of the best killers in the world, primarily because I take the high risk cases. I have a long history of escaping undetected. Almost no one who may be looking to catch me ever gets to meet me. Those that do don't survive to tell anyone."

"I survived."

"You weren't looking to catch me. If you had, if you'd even thought of telling the police my name, you would have been dead."

"Why take the risk of letting me live?"

Yassen smiled that cold smile again. "You're not the only one who thrives on a challenge. One day I may very well be the one to kill you. But when that day comes, I won't shoot you at close range. And you'll never tell the police about me. That's not your style."

Sherlock wanted to protest against this. Except… he wouldn't. The police didn't deserve to catch someone like this. Someone who was clever, who was talented at what he did.

Yassen had been watching him. It felt suspiciously like the gaze he used while deducing their deepest secrets. There was something dark and dancing in his eyes. "Interesting." He stepped away from the counter, and opened the door. "You can leave now. Try to keep yourself out of trouble."

Sherlock brushed his shoulder as he left. He didn't bother to say goodbye – that was something reserved for friends, or at the very least people who liked to consider him their friend. He went three streets before he opened the wallet he's lifted from Yassen's pocket. Credit cards in someone else's name. A driver's licence. A handful of loose change. A folded note.

Unfolded, it read:

You didn't think it would be that easy, surely?

Sherlock walked the rest of the way back home trying very hard not to think of the possibility that he might just have met his match.

It was the third time they met when everything changed for them. For the first time, the meeting felt truly accidental (and yes, just how had Yassen known he would be running down that street?), and for the first time Sherlock felt on even footing with the pale assassin. He was unused to being the one off-footed in conversation.

It has been two months since Yassen had dragged him into the abandoned kitchen, a few weeks more since that first meeting in a shadowy, derelict warehouse. Sherlock was between cases. John was out with Sarah, and Mrs Hudson was visiting family out of town. Consequently, Sherlock was alone in the house when there came a frantic hammering on the front door. He opened it –

– The gun pressed against his forehead. The eyes behind the gun were ice-cool, only the faintest hint of surprise visible. "Let me in."

Sherlock stepped back, keeping his eyes on Yassen. This time, this time I'll get to the bottom of who you are. Yassen followed, gun trained on him still. He wondered, absently, why he bothered. Surely they had already established that he wouldn't shoot him without good reason.

"You?" Yassen asked, once the door was locked behind him. "You, of all people, live here?"

Oh, so you do get thrown sometimes. "Yes, I live here. Are you dropping by for a social call?"

He was sprawled on the hall floor, ears ringing, before he realised that Yassen had struck him across the face. "Now is not a good time to play games with me."

He stood carefully, bracing against the banister. Right. Yes. Assassin, ruthless.

"Up," Yassen ordered, voice clipped. The signs of stress were painted all across him, to a close observer. Sherlock turned, even though he didn't especially want to put his back to him, and walked up the stairs to his living room. His hands were almost steady as he opened the door. Almost.

"If not for a social call, might I ask why you are here?"

Yassen stared at him for maybe half a second, as if formulating his answer. "Something went wrong with my latest job. I need somewhere to stay until whoever betrayed the operation is dealt with."

"So you happened to choose my house out of any of those you were passing?"

The glare Yassen gave him was enough answer – yes, and remember that I can hurt you more than you can imagine. It was also the first emotion Sherlock has seen on that pale face – hot, fiery anger that twisted that something inside him a little bit tighter.

Yassen stays for three hours, enough for whoever had almost caught him to loose his trail. Sherlock doesn't complain, although he has to bite his tongue because he is far too used to having people hop to and listen to his every word. Nothing is the same when Yassen is concerned, and he doesn't like it. He also doesn't like that even after three hours of close scrutiny he still feels like some key fact about Yassen is evading him. His powers of deduction don't fail. To have them do so… it unsettles him. It is only as Yassen stands, shrugs back into the jacket he had sprawled across one of Sherlock's living room chairs and slides the gun out of the holster where he had rested it (and why not? There's no point in keeping it out when Sherlock knows full well he won't shoot him).

"You're leaving." Not a question. Yassen nods in reply anyway.

"Keep an eye out," he says, grinning in a way that holds no humour. "You'll be seeing me soon, I think."

Sherlock tilts his head to the side a little. "One day I'll turn you in, you know."

Yassen moves like lightening, suddenly in front of him and close enough to hear his breathing. "I doubt that."

It's not until he hears the door shutting below that Sherlock realises Yassen kissed him.

The time after that, Sherlock seeks Yassen out. It's not so hard, seeing as there are only so many places an assassin can go in London, and even fewer for one who has just completed a job. Sherlock knows when it's Yassen's work now, recognises the precision of a job even if the method of killing is different every time. He hasn't ever told the police this, pretending every killing is done by some unconnected killer. After all, there's no chance they'll work it out for themselves, and much as he hates it sometimes Yassen is absolutely right – Sherlock won't turn him in. He can't, not after that kiss (and was it even that? Just a swaying forward, a sudden crush of lips against his and then the door slamming as Yassen strides out into the night). But in a way it's because of this that he feels the need to go find Yassen after another body turns up like a calling card.

He doesn't ever consider it strange that Yassen kills to get his attention.

Sherlock find Yassen on the third try, in a frankly disgusting flat in a run-down neighbourhood. It's a perfect place for a contract killer to stay – out of the way, not in keeping with the amount of money he has so less likely that the police will look there, and with neighbours who know better than to ask questions of the strange people who come and go in their building. The lock is easy to pick, which is either an oversight on Yassen's part or (more likely) he wanted Sherlock to find him. This theory is confirmed as soon as Sherlock steps through the door.

"What took you so long?"

"You're better at disappearing than you think."

Yassen tilts his head slightly, eyes intent. "I don't think so. Maybe you just don't know me as well as you think."

Sherlock has to forcibly remind himself that Yassen is a dangerous person to tangle with. "Perhaps."

Yassen stands, suddenly, and Sherlock takes a step backwards, feeling the door behind him close to his shoulders. It's simple self-preservation, because there is danger visible in Yassen's every move. Yassen follows him, deliberate, puts and hand on each shoulder, and kisses him, rough, controlling, leaving no room for argument or escape. This time Sherlock cannot deny what it is. Instead, he breathes out in a gasp that gets trapped between their lips, that snags against his teeth and Yassen bites his lip, almost gently. Sherlock breathes out again even though he can't remember breathing in, and then remembers where he is, why he is here, and shoves Yassen away. It's a dangerous move, but bizarrely he… trusts Yassen. It's similar to honour among thieves – Yassen won't hurt him, and he won't turn Yassen in.

"What –"

Yassen laughs, cutting him off. "Don't pretend you don't understand, Sherlock, I know you do."

Curse him, he's right. Sherlock understands perfectly. This is why he's never been interested in anyone before – no one has ever been worthy of that interest. Yassen is. Yassen understands him, for the simple reason that they are very similar. Both in it for the excitement, for the challenge, not the money. Both outcasts. Both people that society would rather not think about until they were needed. And Yassen is a puzzle to him, someone he wants to figure out but just – can't.

"Sherlock." Yassen's voice calls him out of his thoughts. Sherlock looks up, meets his eyes. When Yassen kisses him again, he relaxes, accepts, because this is what that twist inside him was trying to tell him.

Sherlock stops thinking.

Sally Donovan, who hates him for no real reason other than the fact that he exists, once said that one day Sherlock Holmes would be the reason for the body she was investigating. She's wrong, although not by much, all credit where it's due. Sherlock doesn't have to be the one to leave a body there. He has someone to do it for him. It's not a conventional way of showing someone you care, but neither of them are conventional.

This time, the man is dead, throat cut neatly and expertly. Sherlock almost smiles when he sees it, although not quite. Of course it's Yassen; he can see it as clearly as if it was written on the man's chest.

"Any ideas?" Lestrade asks, glancing between Sherlock and the body.

"Several. There are signs of a struggle, you can see there, so it could well have been self-defence, and you see that mark there? Clumsy hands, not someone who knew what they were doing…"

After all, it's easy for Sherlock to lie. He picks all the elements of the death that lead anywhere and twists them, just enough, that they point somewhere other than Yassen. He doesn't worry about the police finding out. If they could solve the case on their own, he wouldn't be there, and they're all far too trusting to suspect him of misleading them. None of them expect him to have a connection to someone that would override his desire to always be right. And every time a body turns up, killed with précising and with mistakes that are just a little too deliberate to Sherlock's eye only, Sherlock lies through his teeth at the police officers, waits until he can leave, and hunts for Yassen. Sometimes Yassen finds him first, and sometimes Sherlock deduces where he will be staying this time. They dance like this for two years, and the police never suspect a thing.

This time, after the dead man is zipped up into a body bag and Sherlock leaves, he finds Yassen easily. Cheap motel. He picks the lock on the room door, although he could probably get an extra key quite easily (where would be the fun in that?) and waits for Yassen. He knows it's his room. It smells like him. He doesn't have to wait long – less than half an hour after he arrives, Yassen unlocks the door and makes his way into the room; he doesn't even look surprised to find Sherlock there. His hair is pitch black today, Sherlock regards it suspiciously.

"Black isn't a very good look on you, you know."

Yassen laughs, pins him down in the chair, and kisses him firmly. He smells like hard work – sweat and gunfire and just a hint of blood. "It will wash out. Are the police still falling for your tricks?"

"Mm, and yours. Have you arranged someone to take the fall, or do I have to make up some story about them fleeing the country?" It doesn't strike either o them as odd that they know each other like this.

"I've arranged someone. He's wanted for armed robbery already, so I imagine no one will believe him when he says he didn't do it."

Sherlock smiles. So thorough. No one will ever catch him. If anyone did, Sherlock would – he doesn't know what he'd do. Likely, fabricate evidence to free him. No one but him gets to bring Yassen in to the police. He never will, but if anyone did it would be him. He's the only one to earn that right. "Are you going to tell me the name of our murderer?"

"I wouldn't want to spoil your fun." Yassen's smile is sharp in the semi-darkness. It sends a thrill like electricity through Sherlock. He reaches up for Yassen's next kiss, letting him draw him up into standing. "How long can you stay for?"

No one expects him home at a reasonable hour while working on a case. "Until the first clue you planted gets found."

Yassen's hand has found its way into his hair, possessive but not violent. "Then we have all night."

Sherlock catches the inflection, and smiles under Yassen's lips. Thoughts of the case can wait until morning. He doesn't need to deduce anything here. He already knows everything he needs to.

Neither of them speak about the future. They both know that one day it is very likely that Yassen will be ordered to kill Sherlock, or that Sherlock will be forced to bring Yassen in. It isn't taboo, not really, they just don't feel the need to discuss it. After all, talking about it won't change the reality of it. For now, all they need is each other, a suitable scapegoat for the crime, and a shadowy meeting place. Recently, Yassen as taking to calling Sherlock, or maybe texting him, instead of leaving a body. He likes that. Yassen never tells him when he's about to kill someone, and leaves Sherlock to work it out from the subtle clues he leaves, just for him. He likes that even more. So Sally was right, almost, although he would never tell her that. He is the man that puts those bodies there, because he can't deny (and neither can Yassen) that they are there for him. A game for him to play; a chance for him to play the hero everyone expects him to be and for him to trick every single one of them.

"Have you got any leads, Sherlock?" Lestrade will ask him.

Sherlock will smile, in that way they all hate. "Yes." And then he will lie. Because Yassen is his, and they can't have him. That twist inside him aches a little tighter, fierce and protective.

They will never have you.