"Is that all you wanted me for?" Annie asked Lestrade, standing up and putting on a grey cardigan that reeked of damp and mothballs. "I really dunno if I can tell you anything more."

"No, that's fine for now," Lestrade said, glancing over his shoulder at Donovan. She was sitting at the bar with her pint, seeing off George Hutchinson, who was waving to her from the doorway. "Where are you off to now? Or should I ask no questions and be told no lies?"

"Something like that."

"Okay." Lestrade had promised Annie that he didn't care what she did for a living, and now he had to stick to it: if word got around that the Met detectives investigating Tabram and Nichols's murders were getting judgmental about street prostitution, they could kiss goodbye any chance of decent witnesses contacting them in the future. "But you've got somewhere to sleep tonight, right? Money for a bed?"

"Oh, I should get on all right," she said. "I always do."

Lestrade exchanged a look with Donovan, who had seen Annie preparing to leave and wandered into earshot. "The thing is," he said, "My duty's to protect and serve. Which means I can't really wave you off if I don't think you've got somewhere safe to go."

"St Andrews' Lodging House," she said, pulling her hair out from under her collar. "Dorset Street. I don't turn tricks for booze or fun, Mr. Lestrade. Every now and again, and just enough to get by. I didn't do it at all until my husband died."

This was beginning to form quite a pattern. Who knew so many of London's street walkers were middle-aged women who'd had the spouse-and-two-kids and lost them somehow? Lestrade had never worked in Vice and had no more knowledge of its workings than someone outside the police force, but he did have a friend who'd retired the year before after spending the last fourteen years of his career as a DCI there. Perhaps it was worth giving Keith a call and investigating further…

"Okay," he said. "Stay safe. You've got my number."

She nodded, though she looked like she was trying to humour him and he had grave doubts as to whether she'd call him for anything short of being stabbed to death at that very moment. Perhaps he'd better have given her Donovan's number? But then, Donovan wasn't known for being approachable. Lestrade watched from the doorway of the Blind Beggar as Annie made her way up Whitechapel Road toward Brady Street. He was musing on the case and only remembered Donovan was still there and had gone back to the bar for her pint when he heard her swear.

"What?" he hurried over. She was holding her phone, and swung her legs out from the bar, as if preparing for action.

"Daily Mail online." She gave him the phone. "They've named Leather Apron: according to their sources, he's some bloke called Jack Pizer. Been in and out of the system for years for assaults, public disturbances, that kind of thing. Name ring a bell?"

"No. But then, it wouldn't, would it? Never worked in the area."

"Greg, that article went up seventeen minutes ago, when you were still over there talking to Annie. So how the f—"

"The women you said were too scared to talk to you. Most of them are probably a couple of quid away from being homeless, or desperate for a fix, or both," Lestrade said, still scanning the article. He knew a number of journalists he relied on when it came to cases; the press could, when used right, help the police rather than hinder them. But he knew nobody from the Daily Mail. "I bet some bastard bottom-feeder of a journalist offered one of them a payment she couldn't refuse."

Donovan raised one eyebrow. "You think I should have done the same?"

"I know what a bribe is, Donovan," he said, irritated. If any of his detectives offered a witness one in exchange for information, it would be the end of their career, and possibly even send them to prison. He also knew that half the information Sherlock dredged up on a case came from his free-and-easy use of bribery. He'd always looked the other way: if Sherlock Holmes, a civilian, wanted to bribe people, that was his business. But this wasn't Sherlock's work. Someone had beaten him to the punch. "So they've gone and named him." He pulled one hand over his chin. "Helpful in the short term, maybe, but that's serious, for Pizer and for us."

"Libel."

"I'm thinking more about his safety." He gave the phone back to her. "Start calling everyone in, unless they're doing something crucial. Meeting at headquarters in an hour."

"Mrs. Watson…?"

Molly stirred and opened her eyes—and for a good three or four seconds, had no idea where she was. Then she remembered: she was in hospital, she'd dozed off, and John was still fast asleep on the bed beside her. Her doctor, a fiftyish woman she knew as Dr. Creighton, was standing at the edge of the bed, looking amused.

"Oh," Molly said, pulling herself upright but trying not to wake John. "I'm sorry, I didn't mean to fall asleep…" She checked on the twins. Sophie's eyes were open a little and Louise was waving her tiny hands around, but neither of them cried much, even when they were just waking. John was apt to comment that it made a refreshing change from Charlie, but she knew this for what it was: a cover for worry.

"It looks like you could do with a kip," Dr. Creighton said. "I'm sorry to wake you. Plenty of rest is the best thing you could be doing with yourself at this stage. Wouldn't hurt the new dad either, I dare say."

Clearly, Molly thought with a little note of triumph, she didn't see John as a danger to anybody. By this time John had woken too, and was scrubbing at his eyes with the heels of his hands.

"How are you feeling?" Dr. Creighton asked her.

"Good," she replied, before she remembered that if anything, she was supposed to be playing down her health. Too late.

"Okay." Creighton pulled Molly's medical chart from its slot at the foot of the bed. "I just want to have another look at the wound site, Molly, and take your stats. If everything's normal, you'll be able to go home around lunchtime tomorrow."

Molly glanced at John before she could help herself. Oh my God, he's going to…

But to her surprise, John looked composed, even if he hadn't quite made it the whole way to pleased. "Okay," he said. "Yeah, good. We'll have follow-up at home, though, right?"

"A week of daily visits from the community nurse, and as much counselling as they'll let me prescribe."

Molly stopped herself from making a face. She could do very well without the counselling sessions, thank you very much. She saw movement in the crib out of the corner of her eye and slipped one hand in to comfort Louise, who sounded like she was trying to cry after all. And that made two of them. She swallowed a lump in her throat.

"What about the twins?" she made herself ask calmly. Sophie and Louise were being treated under a different doctor, a Dr. Hussein, and she knew Creighton couldn't possibly give her an accurate answer, but anything was better than nothing.

Dr. Creighton smiled. "You know I'd hate to give you an answer and have Dr. Hussein tell you something different," she said. "I'm an Ob-gyn, not a paediatrician. But both your girls seem to be coming along: putting on weight, no major complications except that they were so premature. Sophie might be out in a week or two, Louise perhaps a week or two more."

Molly felt it like a blow to the chest, even though she hadn't expected any other answer. A week or two. A week or two. Which meant that if Louise's progress continued to be more sluggish than her sister's, she mightn't be able to take her home for a month. Through sheer force of will, she managed to hold it together until both consultation and examination were through and Dr. Creighton had left, but only just.

"Hey," she heard John say, and felt his hand on her shoulder. She couldn't bring herself to look up at him.

"Sorry," she said. "No, I really am sorry this time. I said I wouldn't get upset. I knew this was going to happen…"

"We both did, Lolly. There's nothing we can really do about it, so we're just going to have to get through it, right? Anyway, just think how thrilled the cats will be to get you back."

Molly snorted with laughter at this unexpected conclusion, even though she was still crying. John pulled a couple of tissues from the box on her bedside table and handed them to her.

"You'll visit the girls?" she begged. "Every day?"

"Molly, of course." He squeezed her hands. "Of course. For hours and hours. I'll sit here and watch them sleep if it'll help."

John would, too, and she knew it. Right in the middle of a case. Being everywhere for everybody; putting thirty-six hours into a single day. Was it a matter now of if John would break, or when?

Maxine, proprietoress of the Blue Dolphin, was not what Dyer expected the madam of a brothel to be like. With her ironed blonde hair, extravagant purple nails and smart black-and-white power skirt-suit, she reminded him of Hayley's mother. Even more bafflingly, she and Sherlock Holmes were on a first-name basis with each other.

"None of your girls have reported any suspicious customers?" he asked her.

"Most of them are suspicious, Sherlock." She was standing behind the reception desk, going through her client lists, though she didn't seem to be looking very urgently. Without much else to occupy him—the place was closed, and nobody else seemed to be about—Dyer had been looking at the bright orange wall behind her and trying not to zone out completely.

Sherlock pulled a face. "You know what I mean," he said. "Come on, we're not here out of idle curiosity. Someone is out there, and he's dangerous."

"I heard he's targeting street girls, not our staff."

"He's targeting whoever happens to be around when he wants to kill. More than that, he's getting increasingly confident. Mary Ann Nichols was attacked in a public street. It may not be long before he's going on a knife attack in here."

She sighed and took a few steps over to the open doorway on her left, shouting through it: "Miri!"

After being called a second time, a girl with a short shock of peroxide-blonde hair appeared. Dyer was surprised to find she was wearing a t-shirt and jeans, and then surprised that he felt surprised. The Blue Dolphin wasn't open. Very likely she lived on the premises.

"This is a friend of mine, Sherlock Holmes," Maxine said. "And this young fella's from Scotland Yard."

Miri looked them both over in good-natured surprise. "What's this about?" she asked, tugging at one well-pierced ear.

"That woman who got killed in Buck's Row. They think some weirdo's picking off sex workers, want to know if he's been round here. Tell them about the Chicken Man."

Dyer looked at Sherlock. "The Chicken Man?"

"Oh, him. He came in a week and a half ago," Miri said. "With a chicken. A live one. Just under his arm, like. He wanted me to take my clothes off and cut its head off with a knife while he got himself off."

"What the hell…?" Dyer gaped.

"That's pretty much what I said," Miri agreed. "I told him to bugger off, of course. I don't do that kind of thing. He said his name was Ron, but I bet it wasn't. White guy, about forty, fat, had a grey combover. I'd know him if I saw him again. Did he kill that other woman?"

"That's all, Miri," Maxine said. Her tone was placid, but Miri immediately dropped her chin and, after another glance between Sherlock and Dyer, disappeared through the doorway again.

Dyer managed to not look at Sherlock. Maxine had her girls well trained. Perhaps too well trained.

"No," Sherlock said, disappointed. "That's not him."

"Isn't it…?" Dyer spoke up timidly. "Ticks all the boxes. Mental and violent toward prosti- er, sex workers," he corrected himself, catching Maxine's eye. He'd been educated at another establishment, just that morning, that 'prostitute' was a perjorative term, and it wasn't done to use it anywhere except the squad room or the unmarked car.

"No, he doesn't tick all the boxes," Sherlock said. "Wrong psychological profile entirely. Our man is repressed and he's cunning. He'd never do something so bizarre and perverted in such an open manner, and then resort to slitting throats in the dark." He turned to Maxine. "That's all—no, actually, that's not all. That Miri of yours is underage."

"Seriously?"

"Sixteen. Seventeen at the most, but I expect you already know that. She's from the north-west suburbs, judging by her accent. Her father is a clergyman. I suggest you send her home to him before the actual vice squad arrive… oh, what now?" he demanded in despair as his phone started to ring. He pulled it out of his pocket and checked it, then looked at Dyer and walked him to the further edge of the room. Taking the hint, Maxine left through the same doorway Miri had.

"What's going on?" Dyer asked over the trill of the ringing phone.

"Lestrade." Sherlock flicked the call onto speakerphone and held the phone out between them. "Hello?"

"Hey, Sherlock. Getting anywhere?"

"Not in the way I'd intended, no. Dyer's here with me. You're on speakerphone."

"Nice to hear neither of you are too distracted. Listen, have you ever heard of a character known as 'Leather Apron'? Real name Jack Pizer. Hangs around the streets of Whitechapel bothering sex workers, or so I'm hearing."

Sherlock sucked in a breath. "Yes," he said. "I know Pizer. He lives rough, but has family in the area. And he's not your man."

"Go on, I'm curious to hear why not."

"You'd know it yourself, if you took the time to think it through properly. He's mentally ill."

"Had a feeling you were going to say that. With what?"

"I don't think he's ever had a real diagnosis. He self-medicates with heroin. A junkie, if you'd like to call it that. Between those two things, Pizer hasn't the sense not to walk into traffic, let alone slip past three patrolling police officers."

"But he has a history of violence?"

"Yes. He's been in and out of the lockup in the nine years I've known him. He doesn't understand the concept of a restraining order, so these are really only temporary fixes. He's violent with women, and attacked one woman with a bullwhip last March. He's clever. He's also subject to fits of paranoia and delusion. But we're looking for someone who commits acts of shocking violence while in a rational state."

"Sherlock, it's not that I don't believe you. But two women have been murdered, and I've just got a plausible tip-off. You know I can't ignore that. I have to find him and bring him in. Do you know where he is?"

A long pause. "No way to know where he is at any given time," Sherlock said. "But all right; I'll play. Let me find Pizer and bring him to you."

Lestrade fought back a yawn. It was now the twenty-first hour of his shift. "Fine," he said. "But you don't have long before my superiors are going to be chasing me for a result."

"I'll go now."

"What about John?"

"He's at the hospital. Let him stay there. I'll text him if and when I need him."

"Sorry… sorry," John called out as he opened the door of 221a. Charlie was already clinging to his legs, and he reached down and picked her up, then wandered into the living room in search of Harry. He found her cross-legged on the sofa, surfing Facebook on her laptop. "Harry, hi, sorry I'm late. Had a lot to sort out, and I just left the hospital. Molly's being discharged tomorrow."

She looked up at him. "Tomorrow? Did you hit the roof?"

"I was thinking about it. She's really not well enough to be released, so I don't know what Dr. Creighton's thinking. But it's not like she's going to keep her in any longer if I insist on it." He took one of Charlie's hands and gave it an absent-minded kiss. "Um. So you're… uh. What are your plans?"

"My plans are to ask Molly when she comes home if she wants me to stay on and help with Charlie." Harry pushed the laptop aside. "And I guess I should ask Sherlock if I'm allowed to continue squatting in his real estate."

John couldn't imagine Molly telling Harry to go back home under the circumstances. But then, the prospect of keeping Harry around wasn't as horrible as it had seemed on the afternoon she'd moved in.

"You want some lunch?" she asked, stretching and yawning. She was dressed down in tracks and a jumper, in a way that spelled out that she had no intention of leaving the flat that day. "Charlie and I have eaten, but I could chuck together a sandwich for you."

"It's fine," John said. "Got something on the way home."

She was looking hard at him, and for a moment he thought she was about to push it. Then she drew her knees up to her chest, tweaked her bare toes, and said, "Where were you earlier?"

"Earlier when?"

"This morning, if you can cast your sleep-deprived mind back that far. You said you were at the hospital visiting Molly, but you didn't go until later. What was all that about?"

"Not the conspiracy theory you're making it into," John said. "I was at the solicitor's office, changing my will. He kept me waiting longer than I thought, and I ran out of time."

"Changing your will?"

"Well, updating it, anyway. Got three kids now." Then, lightly, "And while I was there, just for fun, I took your bequests and left them to Mycroft Holmes instead."

"You know, it actually wouldn't surprise me if you did." Harry spoke lightly, but her expression was more serious. "John," she said. "One of the fun things about being both a woman and a twin is, you get a sixth sense for when your twin might not be telling you the whole truth—"

"Leave it." John felt Charlie flinch and bury her face in his neck.

Excellent parenting there, John. He smoothed down and kissed Charlie's hair, then took a breath to compose himself. "Leave it," he said again in a much more conversational voice. "This is exactly why I didn't want you to move in in the first place."

Harry raised one eyebrow. "You want me to leave?"

Another breath. Another. "No," he said. "Molly's… not good, Harry. She'll need help even getting around the flat, and I'll still need help with Charlie. I can't do it all on my own."

"No doubt you can't, but you have other options," she said icily, turning back to her laptop. "You could, perhaps, pay someone who won't interfere in your business."

"Would it be too much to ask that you don't interfere in my business?" John fumbled for his wallet and let it fall to the floor as he yanked a small card out of it, then handed it to her. "Gilton and Nash solicitors," he said. "St. Bride Street. I was there this morning. Call and ask them."

"They wouldn't tell me whether they'd seen you or not, John. Confidentiality laws, and all that."

"Then you might have to do something new and believe me. I was there this morning, changing my will, because I'm the new and improved John Watson, now with 200% more daughters. That's it. That's all. No mystery."