John knew that Edward now had the loaded crossbow aimed at his back, but he didn't fumble as he unlocked the front door. For a second, he contemplated the obvious next move in this drama - slamming the door and hoping he had faster reflexes than Caitlin. But something stopped him, and it wasn't just that this was the first opportunity he'd had to do something… life-threatening… since Borley Rectory had burned down more than three months before. He led them through the front passage and into the kitchen without even condescending to glance over his shoulder.

"Coffee?" he suggested, picking up the kettle to see if there was water in it. Immediately, he heard a heavy thud. He looked over at Edward, who had the crossbow hoisted at shoulder-level. John looked him over in silence for a few seconds, as the electric kettle started to seethe and roil.

That's one hell of a head injury. Donovan really fought him off. If John had been his treating doctor, he'd have admitted Edward to hospital. At least two broken teeth, probably concussion, and the wound running along his scalp needed half-a-dozen stitches. Once this was all over, he owed Detective Sally Donovan a drink.

The kettle reached boiling point and switched itself off with a snap.

"Oh, I wouldn't do that, mate," John finally said. "You don't want to waste that one shot so early, do you? Anyway, what happened to the knife you attacked Donovan with?"

"Shut up." Edward turned to his sister. Caitlin had been standing at his side, clutching one elbow and saying nothing at all. "Caitlin," he barked at her. "Search him."

She dropped her arms and stared at him. "Why do you want me to do it?" she asked, but it came out not as a demand, but as a timid little plea. John silently noted it. This wasn't the same girl Merivale had interviewed that morning. That girl had been going out of her way to be as difficult as possible. This one was trying to melt into the floor tiles. He thought back to the puddle of vomit Anderson had found at Thompson's crime scene. Despite what television said, it was rare for anyone, even a teenage girl, to throw up after seeing something shocking.

Edward was now looking at his sister like she'd just suggested he jump off a cliff. "Um, 'cause I don't want to go groping him? Gross!"

"Well, what makes you think I want to-"

"Oh, for God's sake," John said. "Should I save everybody some time and effort and search myself?"

He heard a violent crack and saw stars. After a second, sharp pain in his temple kicked in. So did a rivulet of blood, running down his neck and into his collar. It was a few dazed seconds before he realised Edward had hit him with the flat shaft of the crossbow.

"Jesus," he said, gingerly touching his temple and inspecting the blood on his fingers. "That was unnecessary-"

"Shut up!" Caitlin snapped. Then, after a barely perceptible pause, "Face the wall with your hands up!"

John did as he was told, planting both bloodstained palms against the wall. "Listen," he said, hoping that keeping a steady heart rate would help slow down the bleeding from his temple. "You've obviously got some idea in your head that I killed your father. We need to sit down and talk about what happened like rational people…"

Having nothing else to say, he fell silent. There was a long zzzwiff noise before Caitlin grabbed his wrists and duct-taped them tightly together. He heard her breathing in short, sharp bursts, as if she had a head cold, and then felt her fingertips furtively searching around in his jeans pockets. In another second she'd located the Browning. Much as John imagined she must have handled the hessian sack containing David Prosser's stolen cobra, she drew it out clamped between three fingers. "Ed," she exclaimed. "He's got a gun!"

"Great," John muttered to himself. "Just what I needed."

From somewhere over his shoulder, a mobile phone started to ring.

"Come on," June Merivale muttered into her mobile phone. "Come on, pick up…"

Most hostage situations played out in a set number of ways. No more than about half a dozen, generally. It was how crisis negotiators were trained - identify which brand of crazy your perpetrator is, and then try to follow the rules. People who took hostages wanted something. More than anything, they had grievances, and they wanted to talk about them. What sort of a hostage-taker would just not answer the phone when it rang?

These little bastards, apparently. Lestrade's heart sank as he watched her listening down the line.

"You're sure you've got the right number?" he tried, just as she hung up. She rattled off the number, and after double-checking it matched the one listed in his mobile's address book, he nodded. "Have you tried Caitlin's mobile?"

"Tried both kids' mobiles, and John's. Not much else to do except hope they'll change their mind. Blowing up their phones with fifty million calls might make the kids more agitated." Merivale sighed. "If you could do me a favour," she said, "Could you send John's family to somewhere that's… not here? I really don't like the idea having the baby around this close to a crime scene." Then, with a slight smile, "though I'm impressed that it's humanised our crime-solving robot a bit."

After a short discussion on what to do next, both Molly and Sherlock were on their phones. Molly was still sitting in the driver's seat of the car, a blanket draped around her shoulders. She had a finger in her free ear and was talking to someone about post-mortem reports. What that had to do with anything, neither Merivale nor Lestrade were sure, but it was keeping her calm and focused, and that was enough. Sherlock, meanwhile, was pacing around with his own mobile. Probably talking to Mycroft, judging from his tone of voice, and the fact that this was definitely a swallow-your-pride-and-call-Mycroft scenario. He had Charlie perched on one hip, and jiggled her distractedly whenever she started to fuss.

"Sherlock's not a robot," Lestrade objected, a little offended. "Never has been. And he's slack at even pretending to be, sometimes."

"Any chance you're going to be able to convince Mum and Bub to go back to your place?"

Lestrade shook his head. "Not sure I'd want to try," he said. "Molly's as sharp as a tack, June. She could be helpful to us."

"Is the little one helping?"

"Yeah. She's helping to keep Molly and Sherlock sane. And anyway, I want her to be the first person John greets when he walks out of there, which he will-"

"Look sharp," Merivale said, glancing over Lestrade's shoulder. "The sharks have arrived."

A white network-television news van, high-beams on, had just curved into the cross-street. While it was still coming to a stop, the panel door slid open and a camera operator and sound technician bounced out. In the front passenger seat, a well-dressed woman unbuckled her seatbelt and opened the door like a state dignitary. She started talking down the camera lens before her feet even hit the ground.

Oh, for God's sake.

Kitty Reilly was still in crime reporting, though she'd graduated from print to television, dyed her hair brown, and was signing off her reports as Katherine. Either a bid to be taken more seriously as a journalist, or she was desperately hoping people would forget her role in the apparent death of Sherlock Holmes. How she'd kept her career at all was a mystery, though Greg had a vague memory of her making a blubbery apology to the still-apparently-dead Sherlock Holmes on telly, once it'd been established that Sherlock was innocent and Richard Brook was a fake.

Still in journalism. Didn't that just say it all.

She was now regaling her listeners as to the known facts of the siege, including giving out John's full name. Lestrade suddenly thought of Harry. Hopefully, someone had already told her what was going on - she wasn't going to react well if she found out via news bulletin. "June," he muttered. "Keep an eye on Sherlock. Don't let him talk to the press."

"How am I supposed to stop him?"

"Punch him, if you have to." Lestrade left Merivale near the squad cars, making his way through the crowd to where Kitty stood, as close to the police barrier as possible.

"Detective Lestrade," Kitty said, in tones that implied they were old friends. "We're a little shocked to see you here. We had reports come through this morning that you'd died after a snakebite."

"I got better," he said.

"Would you…" Kitty fumbled slightly, unsure whether to take his response as a joke or not. "Would you like to make a statement about what we know about the suspects and their hostage?"

"Sure," Lestrade said, glancing straight up into the lens of the camera. "Oh, are we live?"

Kitty giggled, though he really hadn't said anything remotely amusing, and cast a coquettish glance back at her camera operator. "We are, yes."

"Oh, then in that case, my public statement is this: Fuck off and let us do our jobs. Lives are at stake, and you people come around like vultures, loving every second of it. Now move it, before I call in the riot squad."

For a second, Kitty's mouth gaped so wide that an Airbus could have used it as a hangar. Without even waiting for a response, Lestrade turned and walked back to where Merivale was pretending to give orders to a couple of constables in uniform.

"There goes your promotion," she said soberly, but her eyes betrayed her.

"I'm heartbroken," he said. "And I wasn't kidding about the riot squad, either. They have ten minutes to move, or I'll have them moved."

"I'll help you myself. And I'm going to have Fuck off and let us do our jobs embroidered and framed for your office. You'd make a bloody terrible Liaison Officer."

"Oh, you've no idea." Lestrade stopped. "Oh, of course," he said. "I've been trying to think what Thompson had to do with all this. He was the first one killed, yeah? I'm pretty sure he was the Family Liaison Officer for the Hope murder. Good with kids. After all these years, he was probably the only detective Caitlin and Edward remembered. And one who'd let them into his home if they showed up there, out of the blue."

"Those little bastards."

Lestrade looked down at his shoes for a second. "So they won't talk to you," he said. "What next?"

"We've found the mother," Merivale said. "Karen Hope. Give her credit and everything, she called us first once she figured where the kids were. She's on her way, but she'll be at least an hour. Not sure where her husband is, but since he's not a suspect and the kids don't even like him, I don't think we absolutely need his company."

"How do they get on with their mum?"

"Who knows - if all this was thrown up by a divorce, they might blame her for leaving their dad in the first place."

Lestrade pulled a face. "Yeah," he said. "Been there, done that. Look, before she gets here, I want the press no closer than three streets that way." He pointed. "That one…" he gestured to Kitty, who seemed no longer to be on the air and was talking with one of her sound technicians. "She was at Moriarty's trial. Outside chance she and Karen will recognise each other, and that's the last thing we need."

Their birth names were obviously not Edward or Caitlin. But they'd been using the ones issued to them by the Witness Protection program for so long that they used them now with each other, even though the game was so obviously over. And there was something else about them that John noted almost immediately: Like all siblings, they squabbled.

Since there was nothing else for him to do, kneeling on the floor with his hands bound behind him, John fell to surreptitiously noting the way that Caitlin and Edward interacted with one another. Just something Sherlock had casually thrown out to him an hour ago: one was dominant, the other submissive. And despite her being the one with the gun, it was becoming obvious that Caitlin wasn't the dominant one.

She didn't even seem all that interested in the Browning. She was far more interested in Edward's crossbow, which John sneaked glances at whenever he felt he safely could. A small thing, barely bigger than the gun. The bolt was blunt, but if the bow mechanism launched it with enough force, that didn't matter.

The cut across Edward's scalp was still bleeding. Not heavily, but the blood was fresh enough for him to be leaving reddish-brown fingerprints all over the kitchen counter and, when he opened it, the refrigerator door. He and Caitlin helped themselves to sandwiches - not bothering to offer any to their reluctant host - then retreated to the far end of the living-room for a whispered consultation.

They really hadn't factored in John being their hostage.

John had no doubt whatsoever that if he hadn't been home, they'd have killed Molly and probably Charlie, and then been on their way before anyone was the wiser. But they'd accidentally come face-to-face with him instead.

So why the hell was he still alive?

Not that he minded, of course.

The squabbling had started during the ten-minute period where the landline went off, followed by Caitlin's mobile, Edward's, then his own, and back to the landline again. After a long and acrimonious debate, nobody had answered any of those calls, and they seemed to have stopped for the time being. But by now, all was not well between brother and sister. They stood huddled together the end of the room, whispering furiously, their shadows looming on the far wall behind the sofa. Edward made an aggressive wave of his arm, pointing toward John. His other hand was on his sister's wrist. Caitlin shook her head and hissed something at him.

Edward punched her.

The blow slipped off her left jaw cleft and hit her in the neck. She choked and crumpled, tipping back against the sofa as Edward stormed past John and back to the kitchen. For a second, Caitlin, still holding her throat, met John's gaze.

"Ice," John said. "Put a cold compress on it - not for long."

With a look of contempt, Caitlin thunked both feet up onto the sofa instead. As she did, Toby, who had been taking refuge underneath it, scampered out in alarm. She leapt back to her feet and bounced after him. "Oh, kitty!" she rasped.

Kitty? Even Molly at her most silly didn't patronise the cat with anything worse than puss. Caitlin darted after Toby, cornering him behind one sofa and scooping him up into her arms.

John held his breath.

If he made any indication at all that he was fond of the cat, Edward was probably going to grab Toby by the scruff of the neck and smash his head on the kitchen counter.

Just to get back at him. Just to get back at Caitlin, who was ignoring Toby's squeaks of protest at being confined in her arms. Even though he was struggling, John could hear Toby purring from all the way across the room. Ridiculous cat. Purring in the arms of a three-time killer. Still loathed Mycroft Holmes, who had only ever treated him the way he treated most humans - with polite condescension. John had once thought Toby was rather a good judge of character. But either he was entering his dotage (neither Molly nor the RSPCA had any idea of his age), or he wasn't as bright as previously thought.

"What's your name?" Caitlin crooned at him.

"Toby," John said. "And he bites."

Toby had never bitten anyone in his life, but now would be an excellent time for him to start. Not being able to think of any other way to distract Caitlin, John got to his feet.

"Oi." Edward had returned to his sandwich, though he didn't seem to be very interested in eating it. He picked up the breadknife sitting beside his plate.

"I need to go to the toilet," John said.

Edward looked at him suspiciously. "Why?"

John took a deep breath. "I'm a little nervous," he said, trying not to sound sarcastic. "And, um. If you're not going to untie my hands, you're going to have to help me, if you get the idea."

Edward looked horrified.

"You are NOT making me do that," Caitlin said, and John blinked. She was risking another beating for that, but Edward either didn't hear or didn't register her objections. He crossed the room to John.

"Where is it?" Edward demanded.

John blinked innocently. "Where's what?"

"The toilet."

"Upstairs," John lied. There was a more conveniently-located one in the utility room behind the kitchen, but it had a much smaller window, even though it seemed like a more obvious escape route. "First door on the left."

"Right. Cait," Edward said. "Forget the cat and get up. Bring the gun."

"We're all going, are we?" John muttered. "Scenic trip?"

"Shut your face. I don't want you shanking me with…" Edward stopped, visibly puzzling this one out.

"… A toothbrush?" John suggested meekly.

Actually, now he came to think of it, that one wasn't such a bad idea. Provided he was able to snap the toothbrush handle into a sharp edge…

What the hell was he thinking? He was a Sandhurst graduate, but he wasn't MacGyver. A makeshift shank might work if the kids were unarmed, but one of them had a loaded gun and the other one had a loaded crossbow. A toothbrush just wasn't going to cut it.

With a snarl, Edward pushed him ahead up the shadowy stairs. As they reached the door, Edward opened it, fumbled for the light switch and turned it on, inspecting the room.

John's spirits sank. The window was shut.

The glass was frosted, so there was no chance of making any kind of clear signal out of it, though he could see prisms of red and blue flashing lights that bounced off the mirror over the sink.

Edward turned John around and sawed the breadknife across the duct tape binding his wrists. His hands separated. "Hurry up," Edward said, giving him another shove. "You've got two minutes."

John shut the door behind him and took a deep breath. If the window had been open… but it wasn't. It was also heavy, and clunked so loudly when it was opened and shut that he and Molly had each woken the other up in the nearby bedroom doing it. Edward and probably Caitlin were just on the other side of the door. As he fumbled with his jeans, he could hear Edward breathing heavily through his bruised, swollen lips. Even worse, (and much to the consternation of almost everyone who'd ever visited their house), there was no lock on the bathroom door. Anything that even remotely sounded like a window opening, and Edward would have that door open in half a second.

John zipped his fly up, flushed the toilet, and turned to wash his hands as slowly as possible. Then he wet a flannel and dabbed at the cut on his temple, cleaning the blood off his face and neck until he looked and felt a lot more human.

Tiny split, not even worth a stitch. But all the blood looked gruesome, and had probably helped Edward think he'd hit John a lot harder than he had. John's gaze fell to the hinges of the bathroom cabinet. Leaving the water running, and with a furtive glance over his shoulder, he eased it open and shuffled through the contents. Child-proof caps weren't the most silent of mechanisms…

"Hurry up," Edward said through the door.

"Coming." John put everything back into the cabinet and shut it as quietly as possible. Then he turned the tap off, leaving the bloodstained flannel on the counter.

Nothing for it - he was just going to have to wait for Sherlock to come up with a better idea. Fine. Good. Sherlock always had a plan.

And anyway, John told himself, even if the bathroom window had been wide open, there was no way he'd be able to climb down a sheer brick wall from the second storey without breaking his neck. On the off miracle that he did, Edward was going to kill Toby and probably Casper as well, and then Molly would probably file for divorce.

Did you just decide to remain a hostage for the safety of the cat?

Ridiculous, but there it was. John dried his hands, then folded the hand-towel and hung it back up. "Opening the door now," he said. "Don't shoot."