"Come upstairs." Irene's voice is low and sultry in his ear, the invitation as expected as it is unwanted, breath warm as it traces the shell of his ear.

Sherlock sighs and pretends to take a sip of his whiskey. "I'm working," he says softly, out of the corner of his mouth, eyes trained on the supposed dentist dealing cards at the faro table.

"So am I. So let's work together." She follows his line of sight, her hair just brushing his cheek, enough to make him smirk. "Which one?"

""Doctor" McQuaid. Dentist idea came from Holliday, but his fingers aren't callused, which they should be because he claims to be practicing. Plus, what dentist would not repair his own chipped incisor? Conclusion, he's a fraud."

"What does he want then?" She slides onto Sherlock's lap, arms around his neck, making herself comfortable. He presses a kiss to her forehead, lips trailing down to rest beside her ear.

"Contract killer. He was playing poker with John Masters not long before he died. Based on what Stamford found when she performed the autopsy, there were some commonalities with arsenic poisoning, but it all happened far too fast, plus it would have required a larger dose of arsenic than what could routinely be administered during the course of a faro game. Combined with the chemical stains on McQuaid's fingers, he has some knowledge of mixing compounds. Hence, he's the murderer and the only reason he's still in town is to avoid being implicated in the affair. If he'd run, it would be far too obvious."

Irene turns her head, nipping Sherlock's neck gently, teeth grazing the skin just so. "What do you want me to do?" Her breath ghosts over his pulse point, making his hair stand just slightly on end.

"Distract him. An hour at least. I need to search his room at the hotel."

"You'd better come upstairs later."

He grins deviously at her, eyes crinkling at the corners and she feels her own lips twitch in response. "I'll see what I can do," he murmurs, pressing his lips to hers for the benefit of surreptitious bystanders.

She kisses him back briefly before standing up, smoothing down the fresh creases in her dress, and sauntering over to the faro table, her dark hair flowing onto the red fabric creating the illusion of attractive danger. Instead of waiting to watch her turn on the charm, Sherlock knocks back his whisky, runs his fingers through his curls and puts on his hat. Nodding to Joe behind the bar on the way, he passes through the swinging doors as Irene gets to work on the "dentist."

The town is quiet, midday heat having driven most people indoors as it so often does. Sherlock flips his collar to shield his neck from the glaring sun, and hooks his thumbs into his belt loops, eyes on the ground so as to be less conspicuous. Wandering down a side street, he slips around the back of the hotel and in through the other door.

At this time of day, the majority of ladies are congregated in the lounge with their elegant and occasionally sneering conversation, while their men are in the bar or playing billiards or conducting whatever business has brought them to San Pedro as opposed to Tucson or even Tombstone. This leaves it clear for Sherlock to quietly go up the back stairs, find the right room and pick the lock, all in the space of three minutes.

The room itself is dark, curtains pulled shut even in the middle of the day. Though he isn't fully certain of what he is looking for, the dentist's bag seems a good place to begin. A search shows up nothing of interest except for a bottle of laudanum. Cursing softly to himself, Sherlock moves onto the chest of drawers which present only clothes and chemistry books with a couple of glass flasks. No sign of arsenic or cyanide or anything remotely toxic.

A glance at his watch shows that time is getting short, ticking down quickly and he needs to find something. McQuaid is clearly the murderer, so where are his poisons?

Unless he has them on him. Always a possibility. And why didn't it occur to him sooner?

His coat swirls as he turns towards the door, but McQuaid's trunk catches his eye again, specifically the bottom. The trunk was empty when he checked it, but something like that is always worth a second look.

The door loses its appeal, Sherlock instead throwing open the trunk lid. Empty, of course, as it had been before, but appearing five inches deeper on the outside than the inside.

False bottom.

Taking the small lever from his tool kit, he carefully prises open the decoy trunk floor, every moment aware of how little time is left. The bottom comes up easily, revealing its secret of a water canteen, mortar and pestle, and small, locked box. Fiddling with his lock pick, the box lid springs open. And there, nestled gently inside, is Sherlock's quarry. Clearly identifiable arsenic and hemlock, and what could very possibly be lead.

The grin that breaks across his face here in this dark room is a special, secret one reserved for these moments of breakthrough, for the rush of sweet satisfaction through his veins when the knowledge is his and his alone, before Lestrade and John get to hear his deductions. For a moment, he allows himself to savour this feeling of being right. Then the ticking clock comes back to him, so he carefully arranges the trunk as he found it and slips back out the way he came.

US Marshal Greg Lestrade is pleased to say the least when Sherlock swirls into his office all cheekbones and dramatic coat. The self-satisfied glint in his eye prompts Greg to stand up and put on his hat before even asking what breakthrough the detective has reached.

"Who am I arresting?" he simply asks, buckling his gunbelt and ensuring the pistol is loaded in case of trouble.

"The supposed dentist, Kenny McQuaid," Sherlock replies, sitting back on Greg's desk and taking off his broad-brimmed hat. The curls tumble free, unruly as ever. "He murdered John Masters with a poison comprised of arsenic, hemlock and what I suspect is lead. All of the evidence you need is under the false bottom in his trunk, and he is currently playing faro in the Comique."

Greg sighs, raising an eyebrow at Sherlock but deigning not to comment on the extent of his knowledge. Experience has taught him that when Sherlock Holmes makes a pronouncement on the location of crucial evidence, it's best not to know how he came to possess such knowledge. His lock-picking skills are proof enough. "Are you joining me then for the arrest?"

Sherlock smirks, but shakes his head. "No, but I'll wander over with you in that direction. Miss Adler demands my company."