Sherlock feels his phone vibrate in his pocket - second time in ten minutes. He should really check his messages.
It'll have to wait, though, because at the moment he's got a knife to his throat.
He's not entirely sure how it happened to be honest. One minute he was trailing along after Rhys, ignoring the little moron's continuous stream of complaining as they surveyed a large expanse of graffiti freshly applied to a brick wall down by the train tracks. The next, they'd come upon the author of said graffiti - who, by some stroke of luck or genius or serendipity, had been the same young Asian man from Soo Lin's flat. The one who'd nearly strangled Sherlock to death.
And while that had been exciting for about half a minute (of course, it's all related, it has to be the-!) things very quickly stop being entertaining when the man drops his paint can, whips out a knife, and decides to try and finish the job he'd started.
Rhys screams bloody murder and dashes away into the darkening twilight as the mysterious criminal-slash-acrobat lunges toward the older of the two trespassers. Sherlock raises his fists in self-defence, but the shorter man's more than a match for one underweight and woefully unskilled teenager. Within seconds Sherlock finds himself pinned to the freshly-spraypainted wall behind them with a small penknife pressed painfully into his jugular.
Heart thumping a mile a minute in fright, but Sherlock's nothing if not an actor. He dredges up every ounce of willpower at his disposal and forces his expression to remain neutral - flat, unimpressed... almost bored. Best method to put assailants off their guard: react in an unexpectedly calm manner to violence. Only secondary school lesson he's ever found useful.
"That's barely a three inch blade, you'll not have much luck trying to kill me quietly," he informs his attacker in quite an impressively level voice, considering the circumstances.
The Asian man bares his teeth in an expression halfway between a grin and a snarl. "Who says I want to kill you?"
Heavy accent, sounds like a Chinese native. Interesting. Sherlock raises an eyebrow in mock sarcasm.
"Well if you were going for a polite introduction the knife might be a bit muc-"
He cuts off with a hiss of pain as the shorter man digs said knife into the side of his neck - well away from any major vessels but still deep enough into the muscle to hurt like hell. Sherlock's stoic expression cracks for a moment into something like primal terror, feeling the handle of the blade press hard against his still-bruised windpipe. Oh good lord this man might actually kill him. No no no no this is not how he wants to die!
"You are scared," the man asserts, grinning wicked through a sharp-eyed glare. Sherlock swallows convulsively and wrestles his face back into a blank stare. The man smirks and continues; "Just a child. Yet you follow me." He pauses, eyes Sherlock up and down with an appraising scowl. "Nothing but a skinny boy. What does he want with you?"
"Who?" Sherlock asks with a slightly confused blink.
The man doesn't answer him, just removes his knife from Sherlock's neck and flips it shut. Sherlock can't help instinctively pressing a hand to the sluggishly-bleeding cut at his throat as he leans into the wall, eyes his would-be murderer warily. Should he try to run, or...? No, bloody hell - the bastard's probably fast enough to catch him without so much as breaking a sweat. This is looking very, very bad.
After a pause the man nods to the collection of graffiti behind Sherlock's back.
"Thinks you'll figure it out, thinks you're clever," he says with a sneer. "Doesn't want you killed."
"How considerate of him," Sherlock replies without thinking, tone dripping with insipid sarcasm as he rubs at his neck. "You are aware that goal might be better accomplished if you'd avoid stabbing me in the ne-" Quick as lightning the Asian man lashes out with the flat of his hand and catches Sherlock across the face, making the teenager lose his footing to slide down the bricks in an undignified heap.
"Make no mistake, you would be dead days ago if it was up to me," the acrobat hisses. "But I follow orders."
Sherlock lifts his head, suppressing the urge to retort with any of a deluge of possible sardonic rejoinders to that statement now flitting through his brain. No, he decides... continuing to mock a man who's just confessed a desire to murder him would doubtless be a poor idea. Instead he pushes himself up into a slightly less haphazard sitting position against the wall, glares up at his attacker.
"A cipher's useless without a key," he snaps, beginning to grow annoyed despite lingering fear. What, so he's become some sort of plaything for a master criminal? Is this all nothing more than a ridiculous test? "What do you use? A one-time pad, some sort of rhyme? Numbers to letters through any of a million different methods. How does this mysterious benefactor of yours expect me to deduce it, then; trial-and-error?"
The man scoffs. "Telling would be cheating."
"Your stupid rules, not mine," Sherlock retorts hotly. Then he raises an eyebrow. "Or maybe you don't know? You're just the aerosol lackey, are you? Boss must have sent you out to-" This time the kick aimed for his ribcage is anticipated, he easily jerks out of the way and shifts into a standing position with a single fluid motion.
His brief display of coordination seems to have amused the acrobat, who quirks a dark smirk at him.
"A book," the man says simply.
"What book?" Sherlock asks, knowing he most likely won't get an answer but feeling it best to try regardless. "Numbers to pages? Or some other system? How common is it? A reference everyone has or is it unique to members of your group?"
As expected, the criminal just turns to leave. Sherlock just barely stops himself from stamping his foot in frustration like a child. What, he's supposed to figure everything out from a single enigmatic word of a clue and a load of yellow paint? The hell do they think he is, some kind of psychic!?
"Hey! You can't just run off without-! Get back here, you bloody prick!" But it's no use - the man's already vanished into the now-murky twilight of a set winter sun. Sherlock growls to himself and spins around to regard the wall he was nearly murdered against. Fine, if the bastard's going to insist on being unhelpful...
Yellow symbols painted in rows across the bricks; longer message than any of the others. Lower letters slightly smudged by Sherlock's having been shoved into them but not unreadable. Some sort of threat? Information? There's no way to tell without a key of some sort. A book, though...? Has to be something common. A rare item would too easily tie different members of the organisation together. More likely some random text anyone could pick up and flip through without drawing suspicion.
He stands and stares for a few minutes more. Eventually however the cold begins to seep through, overpowering the waning warmth of adrenaline with tendrils of ice in his veins. Shuddering in an involuntary shiver he wraps one arm around his torso and digs out his phone with the other hand. A photo of the message is more secure, anyway. Can't be erased so easily.
Walking back to a more populous area of the city is an exercise in misery. It's bloody freezing out, he's stiff and sore from the scuffle, people he passes on the street keep giving him odd looks. Probably has spraypaint all down his back, he realises after a few minutes' walking and being stared at by fellow pedestrians. Face and neck definitely bloodied, bruised - no wonder they keep looking... but then as far as anyone knows he's just some unfortunate wayward vandal. Nothing to fret over, not likely to call in authorities. Easily ignored.
Besides, he's far too busy mulling over this newest development to care what people on the street think. Every possible book the criminals could be using runs in endless lists through his head. Common... has to be something common. Dictionaries and textbooks, thesaurus... but do they use the same method for different cities? They can't be strictly London-based. Needs to be something available everywhere, something subject to change whenever it's cracked by law enforcement.
As he walks he stares contemplatively at the pavement, which turns out to be a mistake as without being able to see where he's going he soon runs headlong into a tourist couple standing by the kerb.
"Oof!" the older man coughs, drops the book he'd been holding as he unexpectedly takes a bony shoulder to the sternum. Sherlock stumbles back in shock but quickly rights himself. Beside them the man's girlfriend's already started scolding him for being careless.
"Pass doch auf!" she yells angrily. "Hast du Tomaten auf den Augen?"
"Entschuldigen Sie, bitte," Sherlock apologises, switching to German automatically. As he bends down to pick up the man's dropped item, however, he freezes - a guide book of some sort...? Oh, it's the London A-Z! Perfect!
A flash of excitement shoots through his chest, and instead of returning the book to its rightful owner he snatches it up, feverishly flips through the pages. Thinks back to the original cipher in the bank - had to have been a warning of some sort, simple threat. First number was fifteen, so...
"Hey! Gib mir doch mein Buch zurück!"
"Minute!" Sherlock snaps as the German couple demand their book back. Fifteen... fifteen... ah! Yes! 'Deadman'! First entry on the page - fits perfectly! Without even thinking he pulls out his phone, a notebook and pen from his bag, and begins translating the message from the train tracks right there in the middle of the pavement. The German couple hangs around complaining for a few seconds, muttering something about how the English are supposed to be polite, then apparently gives up on getting their city guide back and walk off. Sherlock's not listening, of course - far more interesting things on his mind.
Not ten minutes later he's rushing up the stairs to John's flat, the notebook clutched triumphantly in hand along with his phone. He's got it - jade hair pin, tunnel, nine million. Cipher successfully cracked!
Bursting into the flat without bothering to knock, already yelling about what he's found as he skids excitedly around the arm of the sofa to face the vaguely John-shaped form sitting there.
"John! I've solved it! One of them stole an artefact, that's why they wanted them both dead - and Soo Lin's involved somehow, it's all got to do with the London A to-"
He cuts off mid-sentence, staring at the person in front of him. That is most definitely not John.
"Er... hello," Sarah says with a small, slightly nervous smile. She sits curled up on John's couch with an afghan over her and a cup of tea, facing the telly which seems to be paused in the midst of some film. Sherlock snaps his mouth shut with a frigid glare and retreats a step toward the coffee table. Oh, right... she's still here. He'd forgotten their little date was tonight.
"Where's John?" he asks in a clipped tone. With an annoyed scowl he sets his bag down on the table behind him, along with his notebook and phone. No reason to keep carting everything around.
Sarah's smile seems to go a bit odd - something like fondness mixed with a hint of worry. Sherlock's expression darkens. What's she got to be fond of? Or worried about!?
"Actually, he's just gone out looking for- oh!" She cuts off as there's a knock at the door. They both look over to the entryway. "That's probably him, then. Or the food?"
"I'll get it," Sherlock snaps before Sarah can get up. Too impatient to even consider how strange it is that John would bother knocking on his own door, he just rushes over and flings it open with an irritated huff.
"There you bloody... are...?"
He trails off with a confused blink, because the man on the other side of the door is most decidedly not John. There's no chance to do anything more than stand there staring like an idiot, however, as not half a second after Sherlock registers the sight of a solidly-built Asian man standing on the threshold instead of his friend he finds himself staring into the business end of a handgun.
No seam down the middle this time, no sheen of plastic - this weapon's entirely real. He feels the blood drain out of his face as he involuntarily takes a startled step backwards into the flat.
The man grins in amusement at Sherlock's hasty retreat, but doesn't let him get any further than a single step. With a deft motion he flips the gun over in his hand and lashes out with the hard stock.
Sherlock feels a sharp pain somewhere around the vicinity of his forehead... then, nothing.