A/N- The first scene in this chapter is a rewrite, but the rest of the chapter is new material.

~~o0o~~

A hot underground breeze, reeking of fuel, slapped Sherlock in the face as he made his way onto the train platform. At the far end he spotted Sam looming over another person who, for a few seconds, was obscured from sight. Then Sam turned and Sherlock saw Matthew shrunk up against the tiled wall of the overhead staircase, his overnight bag clutched to his chest like a shield.

"Obliged," Sherlock broke in, offering Sam a handshake with a banknote tucked between his fingers.

"'This who you were looking for?" Sam asked.

"Not your business." Sherlock dismissed him with a vague wave of his hand and turned to Matthew, who was watching all of this curiously. "Well," he said cheerfully. "You and I are currently standing under the watchful eye of about fourteen CCTV cameras. You really don't get the point of this "running away" business, do you? Follow me. Keep up."

Matthew had lived in London for ten years and knew many of its streets and features, but he never forgot his walk through the streets with Sherlock Holmes that drizzly morning. Avoiding cabs and, Matthew supposed, avoiding CCTV wherever possible, Sherlock led him on the most convoluted route he'd ever seen, through lanes and up and down staircases and across squares and around buildings. Over an hour later, Sherlock finally stopped at the junction of Snow Hill and Cock Lane.

"There used to be a ghost in Cock Lane," Matthew ventured, a little out of breath from the long, brisk walk. "Hundreds of years ago."

"Really?" Sherlock drew something out of his pocket and glanced at Matthew over his shoulder, one eyebrow raised. "Did it die?"

Before Matthew could respond, he turned to a doorway and put the key in the lock, shoving it forcefully with the ball of his hand a few times before the sticky door gave way and creaked open. He pulled the key out with the same degree of force.

"What is this place?" Matthew asked.

Sherlock reached out and flicked the light switch on the right side of the doorway, which threw a weak, greenish glow over the room in front of them. The whole apartment was little more than one room; in it was a modest single bed with an iron frame, well covered with blankets that smelled slightly of mothballs. It led into a kitchenette, newer and better put-together than the one at Baker Street. There was a microwave and kettle and a bar fridge that hummed in a businesslike way. The lintel was so low that Sherlock had to duck his head as he went into the kitchen. Beyond it was a closed door that Matthew imagined would probably lead to a bathroom.

"Bolt hole," Sherlock said abruptly, after such a long silence that Matthew took a second to work out what he was getting at. He'd just realised that at least part of what he thought was the smell of musty bedclothes was actually the rain-soaked smell of the clothes he was wearing.

"Is there anything to eat?" he asked hesitantly.

Sherlock frowned for a second, as if the idea that Matthew might need food had only just occurred to him. Then he cleared his throat. "Well, I suppose I could find something," he said distractedly, opening a cupboard that seemed to contain not much more than olive oil, salt and pepper. "If not, I'm sure you'll survive until your father –"

"No, please," Matthew suddenly begged. "If you tell him where I am, they're going to arrest me…"

"What makes you think he'd tell Merivale where you are?"

Matthew frowned. "Because he has to," he said. "It's the law."

Sherlock, hand still resting on the cupboard door, stopped and looked at Matthew in silence for a few seconds. "You think so?" he said thoughtfully. It had never occurred to Matthew that his father might disregard the law for his safety and wellbeing. "Well." He shut the cupboard door and turned to face him fully. "This puts me in an odd position. What exactly do you suggest I do with you?"

~~o0o~~

Molly's mobile phone rang four times before she finally picked up, which told John that Bob Thompson's autopsy had concluded and she was no longer in the morgue.

"Don't panic," he said immediately, without taking the trouble of saying hello. "Charlie and I are fine, but we're at the University hospital. Vanessa Thompson keeled over at the kitchen table."

"Oh, God," she blurted out. "Is she all right?"

"Yeah. I've just had a word with her doctor, who thinks she'll be fine. Gave her kids a bit of a fright." John, awkwardly shifting Charlie's weight on his hip, craned his neck slightly to look down the corridor, where Robbie and Dean Thompson were sitting in the waiting area, just out of earshot. He'd bought them each a packet of M&Ms from the vending machine in the lobby, and they were quietly eating them as if it were the last chocolate they were ever going to have in their lives. "Looks like I'm the grown-up on duty until their aunt arrives, though," he said. "Should only be half an hour or so. They don't know about Bob yet, and I'm not planning on being the one to tell them. How did… all that go?"

Molly hesitated for a few seconds. "I have to put this in the report that goes back to the police," she said. "But, well, you and Sherlock are still working on this, so I thought it was fair to tell you first."

"Tell me what?"

"Well, two things… the first is that I had a good look, and there was no wine residue in his lungs."

"… He didn't drown?"

"Oh, yes, he drowned… but it was just ordinary tap water, John," she said earnestly. "Which means that if Sherlock found the sink full of wine, the killer must have done that after Thompson was already dead."

It had crossed John's mind that Bob Thompson would otherwise have watched the person about to kill him pouring wine into the sink for no apparent reason. Even so, he'd not expected this one.

But what's it mean?

Leave that one for Sherlock to sort out… once he returned from finding Matthew, or whatever he was currently doing. Even Anderson, John reflected, had a much better chance of making sense of all this than he himself could.

"The other thing," Molly said carefully, "is that I couldn't find anything sinister in Thompson's bloodstream. His blood alcohol level was only 0.03. And definitely no Zopiclone or any benzodiazepine drugs."

John raised his eyebrows. "You sure?" he asked, then quickly backed up with, "Yes, I know, you're sure. Sorry. So he wasn't drugged? Just kind of… wrestled into place?"

"I think so," Molly said. "Someone had bashed him up a bit. Some of his hair at the back of the scalp had been pulled right out, and he had very recent bruising on his shins."

John thought back to Sherlock's "experiment" on Anderson in the kitchen at 221B, and wondered idly what Anderson's shins currently looked like.

"That's… interesting," he said, shifting Charlie again as she started to whine. "Vanessa Thompson was on Zopiclone… I found it in her bag. Her doctor thinks she hazed out due to a drug hangover from last night."

"… What are you thinking, John?"

John let out a breath. "Not sure yet," he said thoughtfully. "But I'll let you know if I come up with anything useful. Sherlock's gone to ground, so I don't know when he'll be back."

~~o0o~~

Sherlock stood in the doorway of the tiny kitchen, deep in thought. In the end he'd relied on the Network again to deliver what he had specified as "food" to the Cock Lane bedsit, and fish and chips had shown up on the doorstep half an hour later. It was the most expensive fish and chips Sherlock had ever bought, since he'd parted with a pair of twenty-pound notes for it and was now running perilously low on available cash. To get any more he'd have to go to a cashpoint, and he was fairly sure his bank accounts were currently being monitored.

He'd imagined that retrieving Matthew would be as easy as grabbing him by the shoulder and shoving him into a cab, directing it back to his father's house. But what was the use in taking him back if he didn't want to be there? He'd just run away again.

He thought of Molly, in the midst of an eight-hour shift at Barts, just around the corner.

"If you're going to stay here," he finally said, "you're going to have to earn your keep."

Matthew looked up at him.

"You're the connection," Sherlock continued. "Between the two victims. Once I work out why you're the connection, catching this killer will become a lot easier. I suggest you start by telling me everything you know about Thompson."

Matthew swallowed, swiping his hand over one cheek. "I don't know him," he finally said. "… Didn't know him, I mean. The only guy Dad's worked with that I've really known is Jake."

"You never met him?"

"I… don't know," Matthew said, shrugging. "What did he look like?"

Abruptly, Sherlock grabbed Matthew hard by the shoulder and whipped his phone screen directly into his line of sight.

"There," he said viciously. "That's what he looked like, dead on his kitchen floor. And Celeste? Oh, I've a photo of her here, too…" He flipped through several photographs. "There. That's what she looked like at the morgue yesterday, Matthew. That's what whoever killed her did to her. That's what everyone thinks you are responsible for. And if you don't want to go to prison for the rest of your life, if you have any interest in finding out who killed Celeste and Bob Thompson, I suggest that you start helping me."

Matthew gave a breathless little squawk, and Sherlock dropped his hand, watching in alarm as the boy covered his face with his hands and took another shuddering gasp, and then another.

Unbidden, John's voice entered his mind. A sound bite from a completely different case, a few years before: Well done, Sherlock, you've managed to work her up into a panic attack.

"Your parents might indulge you in this sort of performance, Matthew, but I haven't the patience for it," he finally said, relaxing his tone a little. He lifted one hand, as if in comfort, then changed his mind. Instead he went to the kitchen, poured a glass of water from the tap, and handed it to Matthew, who grasped it with both hands and gulped it down in between hiccups.

"Sorry..."

"There's no time for crying and apologies," Sherlock said, inexorable. "Whoever our killer is, they aren't going to stop until they're caught, and I can't be certain who their next target is going to be. Your father thinks you're a genius. So be a genius, and help me solve this case."

~~o0o~~

Finally, Vanessa Thompson's sister arrived at the hospital. She turned out to be a tall, angular woman, some years younger than her sister, who approached her nephews so awkwardly that John wondered when the last time she'd seen them was.

He wasn't wondering for too long, however. It gave him an opportunity to slip in and see Vanessa herself. He found her at the far end of the ward she'd been placed in, and John noticed gratefully that the only neighbouring bed seemed to be vacant for the time being. She was very pale, but he also noticed that the only machine attached to her was a standard hydration IV, the sort of thing emergency room doctors gave to people who arrived complaining of a paper cut. Couldn't hurt, rarely helped, but it made people feel like they were both seriously ill and rapidly getting better.

"Hi," he said. "How are you feeling?"

"Tired."

"I'll bet. Your doctor told me that once you get in eight hours solid, you'll feel loads better." He paused. "Your sister's just got here," he offered. "Lisa. She's going to look after the boys for a few days, just while you get back on your feet."

Vanessa passed her hands in front of her eyes. "You must think I'm the worst person…"

John blinked. "No," he said. "No, I've known far worse people than you, I can tell you that. I think you got overwhelmed. I think you've never been on serious sedatives before and you were left to administer them on your own, and it got out of hand. Vanessa," he continued, lowering his voice, "I'm about to ask you a personal question. I need you to understand before I ask it that you don't have to answer it. But if you did, it would really, really help the investigation of who killed Bob."

For a second, John saw in Vanessa the steely resolve of a detective's wife of twenty years. "Ask me," she said.

"What's the name of the doctor who prescribed Zopiclone for you?"

"Oh, I don't know," she said, waving one hand vaguely. "It was at the crime scene last night…"

"Yes." John nodded. "I had an idea that it might've been one working in conjunction with the police. You've never taken it before what happened last night?"

She shook her head.

"Well, I believe you. If you had, you wouldn't have mismanaged it like that." He took a deep breath, leaning with both hands against the rung of the end of the bed for a second. "The reason I'm asking," he said, "is because the girl who was killed – Celeste Biondi - she had a load of Zopiclone in her system when she fell from the roof."

Vanessa's lower jaw dropped. "You don't think I killed her!"

"No, I don't think you've killed anybody. Like I said, you'd probably have never seen Zopiclone in your life before last night… after Celeste was already dead. But if I can track down who prescribed it for you… I might just be able to find where the dose came from that was given to Celeste."

She thought carefully for a few seconds. "I'm sorry." She put her hand up to her forehead. "I really can't remember."

"Well, what did the doctor look like?" John persisted patiently, though he had no idea in the world how he was going to track down one doctor in London by a physical description. "Man, woman? How old?"

"A… well, he was a man," she faltered. "Short dark hair, with a bit of grey in it. He wore glasses – square-rimmed ones, I think."

John nodded, taking in this incredibly vague and unhelpful description in silence for a few seconds. "Okay," he said, standing up straight. "Thank you, Vanessa – that was helpful. Get some rest, okay?"

She nodded obediently, even though John wasn't, strictly speaking, her own doctor. He went back out into the corridor, where he could see Lisa and the boys congregating around the vending machine again. Checking his watch, he saw that it had just gone eleven. He was contemplating telling Lisa to try the cafeteria on the ground floor when the trill of his phone interrupted his thoughts. He answered it without checking the caller ID first, hoping it was Sherlock or, at a pinch, Greg, with news that Matthew had been found safe.

"John?"

No such luck. It was an odd thing, really; Philip Anderson's role in life seemed to be to function as the man you get when you're in need of someone else.

"Anderson. Just the man I wanted to speak to," he said, grimly cheerful.

Down the line, Anderson hesitated. "Really?"

Has he ever been the person someone really wants to speak to? Ever? "Really," John said. "You first, though. News on the case?"

"Matthew had fingerprints taken when he was questioned yesterday," Anderson said. "And while I haven't analysed every fingerprint in Thompson's house, none of the ones I've run through the system for a match have been even close to Matthew's. Things are looking up."

John wondered briefly if things were "looking up" for Anderson, who now had to report that the crime scene had turned up bugger-all in the way of hard evidence. "Does Greg know?" he asked.

"Yes, I just called him. I don't know where he was… out looking, I suppose. And Sherlock isn't answering his phone."

"Of course he isn't," John said, a little severely. "He's on business. Let him surface when he's done with… that part of things." He spoke carefully. It had just occurred to him that his own phone might be tapped.

Anderson coughed.

"Okay," John said after a short silence. "So I'm trying to track down the doctor who treated Vanessa Thompson at the crime scene last night. Do you know who it was?"

"Yes, actually. I have the report right here…" There were a few shuffling sounds down the line as Anderson was evidently going through his paperwork. "Looks like it was Roland Harper..."

"Who's he when he's at home?"

"A GP with his own rooms in Slade Street. We have a pool of peripheral medical staff on call for this sort of situation. One day a month. It was just his turn this time."

John ruminated. Slade Street. I wonder…

"Thanks," he said. "You wouldn't happen to know if he's working this afternoon, would you?"

"No idea, I'm afraid. Can I help?"

"Just keep digging with fingerprints and things on your end. I'll let you know what I find out. Talk soon."

He hung up without any further ado, returning to his phone home screen and thumbing the Google app. Unlike Sherlock, for whom his phone functioned as an extra limb, John hated researching on a tiny touch-screen, but it was the best he could manage just then. After a few false hits, he found the phone number for Dr. Roland Harper, with rooms listed at 247 Slade Street.

Harper was the only doctor who worked those rooms. Even given a late hour at a crime scene, John knew he'd probably not choose to close his own surgery that afternoon if he could avoid it.

He also knew that calling ahead would be a waste of time.

"Okay," he said to Charlie. "Guess what we're doing now? I'm going to need to put you in that car seat you hate so much. And for a change, I really don't mind if you cry about it."