"He has kids," John said in a hollow tone.

He knew it really wasn't the most important piece of information here, but it was the one his brain had latched onto.

"Yes, it explains the–"

"So he goes home every night, reads them stories, then goes out and kills people," John interrupted, staring at the wall past Sherlock. He half felt, half saw the detective hesitate and switched his gaze back to his husband, whose expression was equal measures dark and hesitant.

"What?" John snapped.

"He was a soldier," Sherlock said simply.

John stared at him then shook his head.

"We don't–" he started, then cut himself off, swallowing hard. "It's not– I don't have kids," he settled for saying, knowing that it was irrelevant.

"Tricia does," Sherlock replied.

"She's a doctor, she never–"

But yes, she had, he realized.

"It's not the same!" he said hotly, feeling a surge of anger accompanied by fear and discomfort that only made him angrier. Because Sherlock had a point. But it wasn't the same, he told himself. He set his jaw and felt his hands tighten into fists.

"You misunderstand me," Sherlock said, his grey eyes flickering over John's face.

"How?" John demanded.

"I mean, he was a soldier. That was a job, this is a job. He was trained to kill people and that's what does. He simply does it for someone else now."

"We don't all do that!" John shot back.

"I didn't say that you did, John."

John stared at his husband, realizing that he was breathing hard. And then remembered two windowpanes shattered by a bullet and a dying cabbie. He remembered a gun pressed to Jim Moriarty's throat, and he would have done it, too, to save Sherlock, if Sherlock had only had the sense to run when told to. And he remembered Tricia in her kitchen, standing over the body of the woman who'd held her hostage, the assassin's own weapon in her hand.

"It's not the same!" he hissed again, but to himself this time. He saw the flicker of confusion and concern on Sherlock's features but before the detective could say anything, the sound of his phone startled both of them in the near silence of the hospital corridor.

John saw Lestrade's name pop up on the screen and cursed under his breath. Sherlock stiffened but answered the call, putting it on speaker.

"Inspector," he said in a cool voice.

"We've got another one of yours," Lestrade said without preamble.

"Where are you?" Sherlock demanded as John felt a chill run down his spine, grounding him to the floor.

"The Victoria Embankment, Sherlock," Lestrade said. His voice had the hard and clipped tone John recognized as true anger, barely contained. "Underneath the Westminster Bridge."

It was one of the rare times that John's skills as a doctor were needed at the scene – but not for the victim. He had found himself crouched behind one of the police cars, bathed in the alternating blue-and-red lights, helping a couple officers sip some water. Sally Donovan was there, on her feet but leaning over, hands on her knees, head bowed. Whether she was keeping an eye on the officers who'd thrown up or was keeping herself from being sick, John couldn't tell. He met her eyes and she returned his gaze blankly, her expression tight. He passed her a bottle of water without comment and she took it with a nod.

Despite everything he'd seen in Afghanistan, he was almost grateful to be behind the shelter of the car, away from the body splattered on the road.

Splattered was a good word. John had seen it – only for a few seconds, but they were long enough for a trained trauma surgeon. There was no way to survive a fall from that height, not onto asphalt. The impact had half crushed him, smearing blood and brain matter and skin across the road. Even the officers who were there were looking green and keeping back.

John pushed himself to his feet.

"All right, Sergeant?" he asked Donovan.

"All right, Doctor, thanks," she replied, nodding again. Steeling himself, he turned and left her with the other officers, circling around the car and walking steadily toward the body.

Everyone was keeping back – everyone except Sherlock.

He was crouched down next to the corpse, for once wearing a sterile suit. It had the effect of making him look even thinner than he'd become, and the glow from the street lamps and the emergency lights made his skin look paler. He was looking up at the bridge, a frown of concentration on his face. As John moved closer, Sherlock pushed himself to his feet and walked around the corpse then away from it, toward the bridge, never lowering his eyes.

Lestrade stepped up to John, blue eyes gleaming darkly.

"Want to tell me what's going on?" he asked in a low voice. John frowned and glanced at him.

"There's a–"

"I don't mean the killer, John; we have some idea about that, even if the military police have been handling it. I mean with him." He nodded at Sherlock and John followed his gaze. "I haven't seen him this skinny since – well I think since he met you."

At this, John felt a flash of guilt then anger. That wasn't really his fault. He drew a deep breath and reminded himself that Lestrade hadn't said it was.

"Someone did try to murder his brother," John pointed out.

Lestrade sighed but nodded. John felt a moment's relief at not having to go into their personal life – as much as he liked the DI, he really didn't want to hash out his marital problems with Lestrade. He had no desire for anyone on the Met to know about what was going on, either. It would only make it harder for Sherlock to work with them – and Sherlock would know if they knew.

"Just–" the DI started, then glanced over his shoulder when a car door shut behind them. John looked round as well when Lestrade swore under his breath.

"Please tell me Sherlock did not call him," Lestrade muttered then, moving away to intercept Sam as the Interpol agent approached the scene. John stared. Sherlock had been on the phone in the cab on the way over, texting someone, and John had assumed it was Anthea because Sherlock had said he was going to contact her. He probably had. He'd evidently contacted Sam as well.

John saw Sam stop, look at the body, look up at the bridge, and go pale. He held himself very still for a moment, then set his jaw, giving a sharp, contained nod.

"Why am I here?" he asked in a hard voice.

Good bloody question, John thought, glancing back as Sherlock approached them again.

"Maxen Brace, forty-nine, Shadow Secretary of State for Health. From Cardiff. He's Welsh– well, he was. A Welshman murdered in England technically qualifies as a crime that crosses international borders."

"And the killer is Canadian, Sherlock," Sam snapped. "This already qualified. It qualified when Kelsi Murray was murdered – although admittedly we didn't know that – but it also qualified as soon as this man started killing in England after committing murder in Scotland. Interpol's already on this."

"There you are, then," Sherlock said dismissively. Sam stared at him but the detective had already lost interest and was looking at Lestrade. "What's up at the top?"

"What?" Lestrade demanded.

"Where he was pushed!" Sherlock snapped. "What's there? Any indications of the precise location?"

"Yeah," Lestrade huffed and pulled out his phone. "Graffiti." Sherlock held out a hand expectantly and the DI passed the phone over with a pointed look that was entirely ignored. Sherlock scrolled back and forth between some images and then grinned brightly. The suddenness of the smile startled John – it jarring with the body in the background behind Sherlock and the tension of the officers that surrounded him.

"Brilliant!" the detective murmured, the grin still tugging on his lips. John felt a flash of shock course through him, followed by sudden lightheaded feeling.

Sherlock was enjoying this.

"Yeah, tell me what it means, Sherlock," Lestrade ordered.

"Look at the way he landed," Sherlock said, pointing at the body, then striding back toward it. He turned to glare at them when they didn't move to follow. John cast a look at Lestrade, who sighed and joined Sherlock to stand over the mangled corpse. Sam stayed several steps behind and John didn't blame him.

It was the closest he'd seen the body yet and it was the shock that kept him rooted to the spot because every other instinct inside of him wanted to move away. It was worse than it looked from a distance – the impact had broken so many of the man's bones that he was limp, as if he were made of putty. He had landed face down, but his face was turned slightly to his left. He was unrecognizable, however, his features lost in a mess of blood, his skull crushed. His arms were oddly pinned under his body – John thought he would have instinctively held them out. As if that would somehow have helped. The angle of his back told John his spine was severed and the odd list of his legs below his hips indicated his pelvis was shattered. His clothing was torn here and there and he had compound fractures cutting through his skin.

And there was more than John could see that he knew because he was a doctor. That much damage to the skeleton meant the internal organs were obliterated. Not that it would have mattered if they hadn't been. There was no surviving that.

Tearing his eyes away, John looked up at the bridge through the near darkness.

God, he must have been terrified, he thought. Then he looked back at Sam, who was watching Sherlock stonily. The Interpol agent met his eyes, but only briefly.

"Look at the way he's lying," Sherlock said, crouching down, not at all concerned with the state of the dead man at his feet. "Face down, hands beneath him. If he'd been forced off the bridge backwards, he would likely have landed on his back, face up. He wasn't thrown off – that sort of action is awkward and difficult. We know our killer is between five-foot-ten and five-foot-eleven. Brace was six feet. Not impossible to imagine he could have been picked up and thrown over, but unlikely. It would take more effort than necessary."

"So what?" Lestrade asked. "He was pushed facing the railing?"

"No, because then he could have grabbed hold of the railing – or he'd have been able to, had his hands not been tied. That's why they're pinned underneath him." He tapped the body absently on its shoulder and glancing up at the bridge again.

"And if he'd been facing the railing when pushed, he would most likely have tumbled midair and landed on his back as well. This wasn't a struggle. He was forced over, not pushed over."

"How?" Lestrade demanded.

"Gun, most likely," Sherlock said, in a slightly bored tone, as if this detail was tedious. "Probably the same way he was forced from whatever function he was attending. Formal clothing, good suit, but a bit late for business meetings. And he'd have taken Brace from somewhere public."

"Why?" the DI sighed.

"To prove that he can," Sherlock said. He glanced up at Lestrade and grinned.

"He's showing off," the Inspector murmured.

"Yes, I imagine he is, but he might qualify it as taking pride in his work."

"He's playing with you!" Lestrade snapped.

"No, he's been given orders and is carrying them out creatively and efficiently." He glanced up at the bridge again. "We all fall down," he murmured, that familiar smile playing on his lips. John wanted to close his eyes or take Sherlock by the shoulders and shake some sense into him – he was appreciating this. Not the death, John thought, but the detail. Without meaning to, he turned his head slightly, catching a glimpse of Donovan out of the corner of his eye.

No, he told himself firmly, turning back.

"Kenton didn't fall anywhere," he pointed out, keeping his voice steady, locking his eyes with Sherlock's. After all John had seen in Afghanistan, it came as a shock to realise he'd never seen the body of someone who had fallen from a height before dying. He'd seen people who'd tumbled off buildings after being shot. They had dealt with jumpers in the army, too – suicides – but John had never personally witnessed one.

"No," Sherlock agreed. "But his death agreed with his story."

"What?" Lestrade demanded.

"What's the message?" John asked at the same time.

Sherlock extended Lestrade's phone, which he was still holding, and John took it. He glanced down at the picture and then dropped his head back, closing his eyes. On the pavement above, their killer had drawn two ovals in permanent marker – one complete one, one that was missing the top half, the break delineated by a jagged line. On the complete one, he'd even drawn little stick arms and legs.

This is sick, John thought, echoing Anderson's words from April.

"He was sitting," he said through gritted teeth.

"Precisely," Sherlock said, his voice far too bright.

"Do you plan on telling me what's going on?" Lestrade snapped.

"Humpty Dumpty," John replied, lowering his head again and returning the phone to the DI.

"He was sitting on the parapet before he was pushed off," Sherlock explained. He pushed himself to standing, stripping off his sterile gloves. "It explains the position in which he landed – he was sitting facing away from the bridge. And here we are, unable to put him back together again. However, we can put together where he was and how he got here."

John pressed the heels of his hands against his forehead. Mycroft's going to be furious, he thought.

Lestrade sighed, shaking his head.

"We're already working on that," he said. "Maybe we'll get lucky – maybe someone saw him this time. If he took Brace from some sort of event, then someone had to notice he was missing."

"Hmm, doubtful," Sherlock replied. "Oh, yes someone will notice Brace has gone, but I can't imagine our killer will have let himself be spotted."

"Then what do you suggest we do?" Lestrade snapped. "We're sitting on our hands waiting for him to pick off people one by one!"

"I suggest you clean this up," Sherlock replied, his voice suddenly hard, his eyes narrowing and flashing, reflecting the blue from the police cars' lights. "And find out where he was and how he got here. I will deal with establishing the pattern."

"Pattern? What pattern?"

"He's killing members of a Parliamentary committee, Lestrade, and the less you know about that, the better. The men he's killed so far – there may be a reason he's choosing them in this particular order. You can stand here arguing with me or you can tidy this up and let me find him! I don't need to waste my time answering your questions – just do your job."

He stripped off his sterile suit and left it on the ground, stepping around the body.

"Sam, I'll need access to some Interpol files. I'll text you with the details once I've established them. Come on, John, we're not accomplishing anything here. We've seen all he wants us to see."

Sam didn't respond to Sherlock's comment and John met his eyes. He had the look of a man who was facing several sleepless nights and who was all too aware of it. He gave a curt nod and Sherlock breezed past, dragging John in his wake.

"He got past the guards on Brace," John snapped when they got closer to the police cars. "Sherlock, this is insane! Lestrade's right – we're just waiting for him to pick them off one by one!"

Sherlock rounded on him, expression cold and bright.

"Then we increase the guards and don't allow them to go anywhere public where there's any possibility that they can be caught on their own," he snapped. "Would you like to stand here and complain to me about his capabilities, John? I know what he's done!"

"And you think he's clever!"

"He is clever!" Sherlock shot back. "And while you stand here moaning to me about his intelligence, he's walked away from this. The longer you make me wait out here, the more time he has to plan the next one. Stop dithering and come with me, John! We're going home. I need to establish his pattern."

John stared at him then forced himself to nod, falling into step behind Sherlock. He was livid and he recognized it was because he was terrified. No one knew who their killer was, even the man who had hired him. He was running circles around them, getting in past security everywhere and leaving a trail of bodies in his wake.

And the only person who wasn't frightened by him was Sherlock.