A/N: So here I go with a third multi-chapter WiP. Am I crazy? You betcha!

This one's been floating around in my head for a while. Silly, silly crack.
I've cut off the chapter just before the sexy stuff starts, mostly because I need to get up the nerve to write it! If there are any goddesses of Sherlolly sexytimes willing to give me some writing advice, please let me know (you know who you are...)!

Sherlock didn't want to be in Las Vegas. Everything about it was the opposite of the London that he loved. The lights. The noise. The Americans.

But Mycroft needed someone to infiltrate a money laundering ring that had been flooding England with counterfeit hundred pound bills.

So that's how Sherlock ended up spending a month undercover in the underbelly of Nevada's premiere gaming establishments under the guise of Bill Grey, potential London backer of Austin Henderson's latest exports to the UK.

One month away from London.

One month of playing poker nightly, losing just enough so as not to raise any alarm bells, but winning enough to wipe the smug smiles off anyone who annoyed him.

One month of booze - which had never been his weakness before, but was soon becoming more of a solo habit than a social action.

One month of easy access to narcotics. And for a while, he had been able to hold his demons in check. But when placed on the spot on night by Henderson himself, Sherlock convinced himself he had no other choice but to accept the line of coke that had been offered to him.

He just didn't need the one the next night.

Or the next, especially when it was delivered to him via the oversized breasts of some anonymous call-girl at a party at Henderson's estate.

Within a two weeks, his once dormant addiction was well and truly awake.

The only consolation or justification was that Bill Grey had become accepted into Henderson's fold.

The only problem was that Henderson had provided him with a body man, Smith (not his real name) who was soon a shadow for his every move. Since then, Sherlock had no way to get in contact with Mycroft – and vice versa.

Sherlock didn't know anything about what Henderson had planned for him beyond the places Smith would drive him to. One day a strip club, the next a hidden back-room poker game, and the next he'd be at Henderson's house with all its concomitant temptations.

Without a link to London, Sherlock found himself becoming more and more like his alter-ego and less like himself. Bill Grey was the life of the party, was a friendly drunk, enjoyed the occasional lap-dance, and was careless with his poker-winnings. Unlike Sherlock, Bill Grey had never fought any battles with drug addiction and had no guilt about using socially – and increasingly in the private of his own home.

Because Bill Grey didn't have the voice of Molly Hooper in his head, or the memory of her slapping him for failing her. Bill and Molly would never meet, and Sherlock was more than fine with that.

The days blurred into one another and Sherlock didn't mind. He has a feeling of near tranquillity in not having to decide his every move. He and Smith developed a quiet rapport – bordering on trust. Sherlock was more than willing to go wherever Smith took him, no questions asked.

One evening, Smith drove him to the Bellagio, ushered him inside and rode with him in the lift to one of the upper levels.

At the door, Smith paused and handed him the key card.

"Aren't you coming in?"

"No sir, you wouldn't want me to."

"What's in here?"

"It's your weekly – appointment." Smith wouldn't look him in the eye. Sherlock started to worry about what waited for him on the other side of the door.

"Ok."

Sherlock opened the door and immediately understood the reason for Smith's awkwardness.

Standing on the other side of the room, next to the king sized bed was what Sherlock assumed could only be a high-priced escort. She stood with her back to him and didn't turn immediately when he entered the room. She was in the process of removing her waistcoat, dropping it to the ground to reveal that underneath she wore only underwear – very expensive underwear. A sheer champagne coloured satin bra, lined with matching lace. The bra was complimented by similarly styled panties and lace holsters which held her stockings in place.

Her hair was in a tight bun which she undid, letting the long chestnut hair cascade down her back.

Bill Grey was a lucky man if this was his regular Tuesday appointment.

But he wasn't Bill Grey, and despite forgetting himself in the presence of this woman, Sherlock Holmes didn't do sex – or at least hadn't for some time.

"I'm sorry – " he began before he had even formed an excuse to make her leave.

When she turned to face him, he stopped dead in his tracks.

It was Molly.

"Mo– " he began to say her name but she reached over and stopped him by placing a finger on his lips.

She wore a mask of pure seduction as she lent in to whisper something in his ear. Anyone watching would be certain she was a professional – there was no hint of the woman he worked with at Bart's, a woman he had seen with arms elbow-deep in cadavers on more occasions than he cared to count.

Her words were a warning. "They're listening," she said as quietly as possible.

In that moment Sherlock realised what was going on, what she was doing in a hotel room in Vegas clad in less clothes than he was comfortable seeing her in. She was his handler.

He closed his eyes and sent a silent curse up to Mycroft for dragging her into it.

Molly's eyes searched him for a sign he understood her meaning. Sherlock nodded and she carried on, her fingers dancing on his collar while she lent in again, her lips grazing his ear.

"I don't think they're watching," she whispered, "but we might need to be cautious."

Molly punctuated her meaning by beginning to unbutton his shirt, her lips trailing down the skin of his chest.

Sherlock's eyes closed involuntarily. He didn't want to enjoy the feeling of her hot wet mouth as much as his body clearly wanted to. In an attempt at self-control, he conjured the image of Mycroft's face the moment after punching him in it.

Molly removed Sherlock's shirt completely and headed towards the bathroom.

"Let's have a shower," she called over her shoulder.

Sherlock waited for a moment, trying to collect himself before following.

By the time he joined her the water was running and steam filled the room. Molly's undergarments lay discarded on the floor and she as wrapped in a robe.

All pretence of seduction was gone. "Strip," she ordered.

Sherlock's hand hovered over his belt.

"Do you need me to do it for you?" She said in the exasperated tone which revealed just how much her actions in the other room were for show.

Once naked, Molly ran a cursory glance over his body, her poker face better than most of the opponents he had recently faced. Then she picked up his clothes and threw them back into the bedroom, closing the door behind them.

"You could be bugged," she explained. "We've swept the bathroom, but just in case, we should talk in the shower."

Sherlock nodded. Once she joined him it was like a license for him to let loose everything he'd felt since the moment he realised it was her.

He was thankful for his anger, it gave him something to focus on other than the fact that he and Molly were standing naked, in a shower, together.

"What the fuck is going on, Molly?"

He held her intense gaze with fierce wide eyes. Anything to distract himself from watching the water beading on her skin.

"I could say the same to you," Molly said, her tone equally fierce.

"Clearly I'm on a case. Why else do you think I'd be in this godforsaken city?"

Molly ran her hands through her hair, brushing the wet, errant strands out of her eyes. "You're using again." Her eyes were wide with disappointment.

"Again, it's for the case." He wanted to walk away in a huff, but was trapped, not only by the necessity of their location, but by John's words taunting him in his head:

Drama Queen.

So he stayed put, knowing that Molly wouldn't buy his excuse, knowing he was about to face her wrath. He could almost feel the sting of her hand slapping his cheek, like the burn on his skin was reverberating through time.

"You know, soon that's going to be your only criteria: What can I investigate that will give me an excuse to get high?"

"It was Mycroft's idea"

"The case. Not the drugs."

"So he sent you?"

"He told me what you've been doing. How you've gone off the radar. I chose to come."

"I don't need your help."

"Really?"

"I'm fine."

Molly grabbed his wrist, turning his arm to check for the tell-tale marks and bruises. And repeated on the right.

She breathed a sigh of relief when she saw his arms were still clean. "Maybe for now," she conceded.

Cocaine was one thing, but Sherlock knew that heroin was a much harder demon to defeat. Molly knew it too. She'd been there when he fought it the first time, letting him crash on her couch while going through withdrawals the night before Mycroft took him to rehab. A night full of swearing and shaking and swearing to Molly that he'd never do it again.

A promise he broke.

Molly remained standing slightly too close for Sherlock's comfort. If he wanted to, he could reach out and touch her. The compulsion motivated by a need to comfort her.

He could see that her eyes were beginning to well up. He couldn't tell if she were crying or if the droplets running down her face were from the shower spray.

Sherlock placed a finger on her chin, tilting her head so her eyes met his. "I am fine Molly. But I do need your help." He had to admit he was glad she was there. Although he had gained Henderson's trust, he had no idea how to proceed.

She nodded. "I'll talk to Mycroft. We'll put a plan in motion for next week. Please try to stay clean until then."

Sherlock nodded. He went to turn off the water but she stopped him, her hand holding on to his.

"The surveillance," she explained, "we're going to have to. I mean. Just so they don't suspect – "

Sherlock didn't know what to say. Molly continued. "I mean, just for show – we don't actually have to–"

"Yes. Pretend." Sherlock gulped. He wasn't sure how amenable his body was to pretending not to be aroused by her, especially if his reaction to seeing Molly in her underwear was anything to go by.

"Don't worry, I was engaged to Tom. I'm really good at faking it." She smiled as she turned off the tap and wrapped herself in a robe. Sherlock did likewise.

Emboldened by the fact Molly was distracted towel-drying her hair, Sherlock couldn't resist asking, "I thought you said you two were having quite a lot of sex?"

"I never said the sex was any good." Molly said, leaving Sherlock alone in the bathroom.

Sherlock stood for a moment, considering the strange turn of events. Molly was in Vegas. Molly was his handler. Molly looked amazing in expensive underwear. He and Molly had just showered naked together and now he was going to go and pretend to fuck her like she was his regular Tuesday hooker.

"It's for a case." He told himself, taking a deep breath before heading back into the hotel room.