"No-no-no-no-no! Shit!"

Sherlock, who had reached the bathroom doorway first, felt himself shoved roughly aside as Alan Peters charged past him. The older man dropped down on his knees beside the full bathtub with a force that must have hurt. His hands slapped against the sides of the bath and the water listed wildly as he lifted Detective Sergeant Lauren Jones, still dressed in a sopping white nightgown, clear of the waterline.

"Jesus," Peters gasped, prising open Jones's mouth with two fingers. "Help me!" he barked over his shoulder at Sherlock, who hadn't moved.

"Help you do what? She's dead," Sherlock said. "And any reasonably observant person could tell that she's been dead for some time. Put everything the way you found it and get out."

Peters, still clutching the dead woman, looked up at Sherlock. Then he put his hand on his mouth; an odd, almost juvenile gesture, as if he was going to vomit. "Oh, Christ," he said through his hand. "Merivale was right. You don't even care…"

"Hit me again and contaminate another crime scene, if it makes you feel better. It won't help her, though," Sherlock said. "Do you want to know why I've got an international reputation, with hundreds of solved cases behind me, and you don't? Because my methods work, and I don't particularly care if you don't like me for using them. She's dead. Caring will not bring her back to life. Caring about the integrity of the crime scene will help me find who killed her. Get out."

Peters looked at him in blank astonishment; then, realising that Sherlock meant it, he reached behind him for the door handle.

"Psychopath," he spat at him.

"Your originality knows no bounds," Sherlock remarked absently as he shut the door behind Peters with a bang of contempt. From behind it, he could hear the muffled sounds of Peters storming back down the hall to where Detective Constable Matheson was still waiting for Merivale on the step. He wasn't particularly interested in their exchange and wouldn't have been able to hear it clearly if he had been, but he did register a number of words that weren't considered appropriate for polite company.

Back to business. He was a consulting detective, not a consulting social maven.

He kneeled carefully on the tiles - the dry tiles.

She wasn't drowned - unless she was drugged first. No struggle.

But looking at her face, serene and pale, he discarded drowning as a likelihood - there were no tell-tale flecks of foam and blood around the dead woman's lips. Drowning victims made for very unattractive corpses. But she did look a bit like…

He got back to his feet, tilting his head a little as he looked down at her again and reached for his phone.

It was a closely-guarded fact, even among those closest to him, that Sherlock Holmes had a deep and sincere appreciation for art. His tastes weren't even traditionally high-brow, as John Watson had found out when he realised Sherlock was downright jealous of his knack of being able to make hasty little sketches that showed an appreciation for light and perspective. John had then found out, through some maliciously brotherly comments of Mycroft's, that it was one of Sherlock's lifelong regrets that even his best efforts in that department hadn't produced painting skills that were anything more sophisticated than the sort of things displayed and sold at church fairs.

His artistic sensibilities were the reason Sherlock had even bothered to go after Turner's The Falls of the Reichenbach after it had been stolen. The case itself had been completely ordinary, and he certainly didn't need a pair of diamond cufflinks that badly. He'd taken on a fair amount of stolen art cases in the time he'd been active as a detective, and all for the same reason: desecration of art upset him.

With an exact set of search terms, results weren't far off. He peered at the tiny image on his phone's touchscreen and smiled to himself.

Exactly. Exactly as he'd thought.

Greg Lestrade was never able to fully remember just how both he and Jacob Dyer ended up crouched on the hood of his car.

"Did it get you?" Jake was saying, though for a few seconds it seemed like his voice was coming from the other end of the street. Lestrade felt his shoulder being jostled hard. "Sir? Greg, did it bite you?"

He looked down. In the dim light thrown by the front living-room window, he could see that the toe of his right shoe had a fleck of what looked like water on it. Beyond, just inside his range of vision, a glint of brown scales slithered underneath the front wheel of the car.

"Sir?"

"Um, maybe," he mumbled. "I don't think so. That'd hurt a lot, right?" He twitched his toes. They definitely didn't feel any different than they had ten minutes before.

"Well, I guess we found out what was in the sack when our friend chucked it into the car," Dyer said. "Bloody hell. I don't know about you, but that's taken about ten years off my life. I s'pose it slithered under the seat before we had a chance to see it in the dark."

Calm under pressure, Lestrade thought to himself in some surprise. He'd have never in a million years picked Dyer as someone with nerves of steel, even though there had to be a damn good reason why he'd been fast-tracked through the Uniforms in the first place. Might have myself a temporary partner if Donovan ever decides to bugger off for six months of maternity leave.

He saw a movement in his peripheral vision and whipped his head around. Jake had his phone out and was scrolling through the touchscreen.

"Who are you calling?"

Jake looked like a kid caught with his hand in a sweet jar, and Lestrade conceded that it was just possible that he'd bitten his head off with that last question. "Uh, I'm calling the command unit," he ventured. "… Aren't I…?"

"Hell no." Greg pointed for emphasis. "You haven't been around long enough to know this, but you call anyone from work and we will never, and I mean never ever, hear the end of this. Next time you see him, ask Mickey Varland why everyone in the Sexual Crimes Taskforce still calls him Pissy-Legs." He took a breath. "Um," he said. "Call Hayley's mobile, I guess. I'd give her a yell, but…" He glanced over his shoulder at the neighbours' house.

Jake gave a long sigh. "You're the boss," he muttered, much as if to say that he would much rather Greg Lestrade wasn't his boss at that particular moment. He obediently navigated through to Hayley's number and put the phone to his ear, waiting for her to pick up. For a few seconds it was so quiet that Lestrade could hear the buzz of the open line. He caught another glimpse of the snake moving in his peripheral vision, and took another slow, deep breath.

Across the street, the curtains started twitching again. And while Anita Braach was never going to see him visibly panicking about a snake coiled around his car tyres, she wasn't going to see him actually get off the car when he couldn't see where the bloody thing was.

"Hayls," Jake said into the phone. "I need you to do something for me. Get a torch and come out front, but don't come down the stairs until I explain. Okay?"

As Jake put the phone down and they waited, Greg pondered whether Hayley was really cut out to be the long-term partner of a homicide detective. All signs pointed to yes. The kid could be (and frequently was) a pain in the arse, but she also knew when to stop being one and just do whatever loony thing she was asked to do. In half a minute the front door creaked open and she stepped hesitantly out. Seeing her father and boyfriend still on the hood of the car, she stopped in amazement.

"What are you -"

"Don't come closer," Lestrade said, deciding it was high time that he took charge of the situation, or at least do something more useful than an impression of Man Turned to Stone. "Just turn the torch on and check under the car for me."

Both men winced as Hayley turned the torch on and the beam blinded them. She dipped the torch and swept the beam under the car, like a warship's searchlight. Then she froze.

"That's… yeah. That's a snake," she said dully, as well she might under the shock of suddenly seeing one in the middle of suburban London. "Um. If it was a squirrel or something, I was about to give both of you heaps for being such sissies. Okay. Is the shovel still stood near the back door, Dad?"

It was a couple of seconds before Greg realised why Hayley wanted a shovel to deal with an angry snake. "I thought you were a vegetarian!"

"I'm not planning on eating it afterwards," she said grimly.

"No, don't you dare," Jake broke in, waving his arm wildly at her with more animation than Lestrade thought he'd ever seen out of him. "Good chance it'll bite you, and if you kill it, you're probably breaking about fifteen million Exotic Animals laws and will be destroying a key piece of evidence. It's a frigging cobra. You know, native to Africa. It didn't get here by accident!"

"Are you seriously expecting me to just fold my arms and do nothing while you two are stuck on the car because of that thing? You know snakes can climb, right?"

"Hayley, I'm giving you an ORDER!"

"Give up, mate," Greg mumbled, watching Hayley retreat back into the house and close the front door behind her with a wilful bang. "Unless you're going for reverse psychology. You've met her mother, right?"

Within half a minute Hayley was back, not a shovel, but a broom. She charged down the front steps and over to the car, poked the non-business end under the car gingerly, then jumped back so abruptly that Greg's first thought was that she'd been bitten. "Go," she barked. "Quick!"

He jumped off onto the driveway and hit the ground running, turning at the step to see that both Jake and Hayley had managed to come off okay. Much to his annoyance, he found Jake by Hayley's side. They were both crouched beside the car and Hayley was poking the snake with the broom again, even though there was now no good reason on earth for her to be doing so. A shadow moved from behind the front wheel, and he thought for a second that he could hear a low hiss.

"Right, maybe stop poking the snake now," he said.

"She's sort of cute when she's angry," Hayley protested.

"Yes, lovely. Just, um, call… the zoo, I guess? Hopefully they've got an after-hours number." Or we really will have to call the local force. He took a few steps forward. If Jacob Dyer wasn't bothered by an angry snake, he wasn't going to be bothered, either. "Dyer," he said, "you ever tell anyone about this, and you'll regret it. I know people who'd help me hide your body."

"Like Sherlock Holmes, sir?" Jake suggested, unconcerned by Lestrade's glare.

Lestrade inwardly groaned. Jones - one of his most hard-working, fair-minded colleagues - was likely dead. And now someone had dumped a live snake in his car. Perhaps it was time to concede that if Sherlock said Matthew was safe, he was.

Something was wrong.

June Merivale, parking her car on the kerb outside the Jones residence and getting out, could sense it immediately - something off-kilter and strange, beyond the fact that she was almost certain she was about to enter the scene of a violent crime. Then she realised what it was. She'd expected to see Dave Matheson posted at the front door as a handover officer, to wait for her and secure the scene from onlookers or other interested parties. But she hadn't expected to see Alan Peters standing there with him as well, and no Sherlock Holmes in sight. Peters' shirt and jacket were both drenched.

"Oh, my God," she said as she made her way up the front steps.

"Woman's body found in the bathtub, Marm," Matheson said stiffly, after seeing that Peters wasn't going to do the honours. "Believed to be the occupant, but, um…"

"And you've let Holmes frolick about in there with her, and neither of you are even supervising him. What did I tell you about securing the scene?"

"We couldn't stop him, Marm-"

Merivale resisted the urge to remind Matheson that part of his job involved stopping unauthorised breaching of a crime scene. She was too angry at the real culprit. She stormed into the house and down the hall to where bright orange light flooded out from an open door. Sherlock, kneeling on the floor beside the bath, did not even look up as she made her less-than-silent entrance.

"Sherlock Holmes, this is a crime scene!"

"No," he said absently over his shoulder. "You just walked your footprints all the way through a crime scene. She wasn't killed here. She was killed in the hall." He fumbled for the buttons on the front of the dead woman's sopping nightgown and drew them down a little. "Stab wounds," he said, pointing to the gaping rents in the skin just below her collarbone and over her breasts. "Eight… no, perhaps nine. Could you not smell it as you came through? Bleach. He stabbed her, then cleaned up before putting her here for us to find."

She glanced back into the hall for a second. "Sherlock," she said. "I'm trying to give you a chance, here, because it looks like you were right about the Trent girl. But for fuck's sake, what are you doing in here?"

He finally looked up. "How else was I meant to get a look at the original crime scene before ten forensic techs made a mess of it?" he honestly wanted to know. He waved his phone at her. "I've got photographs, if that's going to help, but I doubt it."

"Right," she sighed. "Gimme." But instead of the views of the hall floor that she expected, the touchscreen of Sherlock's phone displayed the image of a painting. A woman with flowing red hair, lying clothed in a river. Water lilies and other lush flowers adorned her dress and hair, and her eyes and mouth were both slightly open. It was difficult to tell if the painting was of a living woman or a corpse.

"What's this?" she asked.

"Hamlet this time," he muttered. "His girlfriend Ophelia drowned herself - or she slipped into the river and was too mad to get herself back out again. Interpretations differ. That's an 1861 pre-Raphaelite painting by John Everett Millais. You can see the similarities."

Merivale looked down at the woman who had once been Detective Sergeant Lauren Ann Jones. Jones didn't have the same purity of outline as Millais' model, nor the same tint of flame-coloured hair, but the effect was similar. Distractedly, she leaned forward to pull the soaking nightgown up over Jones's breasts again. If it'd been her lying dead in a bath, the last thing she'd want is for a team of detectives to see her naked if they didn't have to.

"But she didn't drown," she said. "She was stabbed - probably with a weapon he brought and took home with him, unless he washed it clean and put it back in the kitchen." She mentally flinched. Well done, June. You've just given him the idea of going through the kitchen before forensics can have a look. "Why does he keep changing his MO?" she asked him. "Killers don't normally do that. It's not safe to start experimenting when you never know if someone's going to walk in on you or what. There's those who have a specific fetish, but it's not the same thing. Say our man gets his jollies making girls go splat by pushing them off a building."

Sherlock sighed heavily. "Celeste wasn't pushed."

"Okay, smart-arse, but that wasn't my point. If it makes your little obsessive tendencies feel better, let's say he's a control freak who delights in forcing her to step off a building of his own accord. Given that, and all the alcohol and drugs she'd had, I'm astonished that the pathology report doesn't say she was raped."

"That doesn't mean she wasn't. If she was drugged she wouldn't have struggled, and he may have been wearing a condom."

"All right, but what I'm getting at is, if you're into that kind of perversion, why in God's name would you switch to drowning people in sinks, or stabbing them to bits and THEN dumping them into a bath? Not to mention the amount of time it would have taken to clean up in the hall."

"There's no carpeting there."

She smiled. "I can tell you don't have kids," she said. "No, there isn't. But blood doesn't come off wallpaper very well. I'm sure forensics are going to rip up the floorboards and find blood in between them, but for all that, he's done a remarkable clean-up job. It would have taken him ages. Over an hour, perhaps."

For all the crime scenes that Sherlock had attended, it had never occurred to him to wonder about the cleanup job after everything had been sorted out.

"Sorry," he blinked. "Did you just say that having children acquaints you with the effect of bloodstains on wallpaper?"

She smiled grimly. "Let's just say that my sons don't always get along. There was a bust-up one Christmas. Teeth were lost. Anyway," she went on, cutting Sherlock off open-mouthed on the verge of interrupting. "So let's say you're the murderer. You come in, stab your victim and then put her in the bath. There's not a lot of blood in the water, so you also wash her off at least once, pulled the plug and refilled the tub. And then, for some reason known only to God, you spend a good couple of hours cleaning up after yourself when you could just have throttled her or something."

Sherlock yanked up the dead woman's hand. "Look," he said.

"Tissue under the fingernails," Merivale said. "Our man will be pretty scratched up, then."

Sherlock nodded. "This killer spent time cleaning up the hall and putting her in the bath, but left his own tissue - his DNA - under her fingernails for us to find."

"Maybe he didn't realise? I mean, in the heat of the moment, the adrenaline - it's possible that he didn't even realise he was bleeding until he'd already left the scene and it was too late to do anything about it."

"Oh, for God's sake, stop being stupid. You said yourself: he spent over an hour cleaning up. No adrenaline rush lasts that long. He'd have noticed. And he left this here on purpose."

In the silence that followed, a fat drop of water bulged out of the faucet and dropped into the tub with a soft plink. Merivale asked, "Why?"

"Because," Sherlock said, "he doesn't care if he gets caught. Which means if he's got unfinished business, he's going to finish it soon."