The feeling of danger overwhelms him, stealing his breath like a sharp jab to the solar plexus. It causes his heart to clench and turns his legs to jelly. Without warning, they will no longer hold his weight.

John staggers. He nearly falls. He would have fallen had it not been for Sherlock's lightning reflexes. He grabs John by the shoulders and holds him steady.

Sherlock's expression, already keen with anticipation, sharpens with concern. "Are you all right?" He whispers harshly even though they are alone on the street. "You've gone pale." He touches his fingers lightly against John's brow. "Your skin is clammy."

He'd like to make an excuse. Say he'd been so busy looking ahead that he'd failed to notice how rough and broken the pavement under their feet was. But he can't. The feeling is too strong to ignore. There's a certainty to it. A profoundness. John knows he's acting dumbstruck. It takes an effort, but he shakes his head to clear it.

"Let's get off the street," Sherlock suggests.

He guides John into the mouth of an alleyway. The stench of it helps clear his head better than a dose of amyl nitrate. The scent of piss and rubbish is sharp and visceral, It's alive.

The miasma that surrounds his brain begins to clear and John is able to take a couple of shallow breaths and loosen the iron bands around his lungs. His knees become bone and cartilage again, able to hold his weight. He's on the verge of coming back completely to himself when the air begins to hum and the pavement under his feet starts to vibrate.

"Get down!" he shouts. He grabs Sherlock in an embrace and pulls him down to the ground as the building they were intending to break into explodes.

They cower as hell-fire rains around them. As the air is pierced by the hooting cry of sirens. It grows thick with dust and hot, singeing the hair on the backs of their necks and hands. The sound become deafening as there are more explosions and more alarms join the cacophony.

Sherlock seems to have a presentiment of his own. Soon the police and the fire brigade will arrive. They will ask awkward questions of any witnesses they find, and Sherlock has been explicitly warned off the case twice already by Scotland Yard. "We should go." He hustles John deeper into the alleyway. They take the long way home, pausing at one of Sherlock's bolt holes to wash away the clinging scent of the explosion and change their clothes before calling in at Angelo's for a late supper.

John is quiet throughout the meal. He picks at his food, earning worried looks from the proprietor and Sherlock both. Knowing his disinterest will only provoke unwanted questions, John doggedly clears his plate and then finishes his meal with a small glass of potent cognac.

"You're not a coward," Sherlock says as John lowers his glass. "In fact, you are the bravest man I know. And yet, in the moments leading up to the explosion, you looked like a man who had just seen a ghost."

"I felt like someone had walked over our graves," John admits quietly. He knows it would salve his dignity to lie about what happened, but he never lies to Sherlock. There's little point in it and it only prolongs awkward conversations.

"A premonition?" Sherlock says. His expression is faintly incredulous.

John doesn't blame him. Not really, it's the sort of woo woo thinking that's antithetical to a rational mind like Sherlock's. He shrugs. "I don't know. If you like. I've never felt anything like it. Not even before going into battle." He thinks of a time when he could have used the sort of foreknowledge he'd experienced. "Not even the day I was shot."

He had known they were in danger from the moment they'd left Baker Street. But they were always in danger in one sense of the word or another – danger from the criminals, danger from the police, danger from Sherlock's own high-handed methods of conducting business – so John had ignored the feeling. He had grown used to it, just as he'd got used to it during his soldiering days. But what he'd experienced had been different. He had known just as surely as he knew that his name was Doctor John Hamish Watson, that entering the building would mean signing their death warrants.

"You must have seen something," Sherlock postulates. "Noticed something on a subliminal level that pulled you up sharp."

John feels his jaw drop as he stares at Sherlock. With an effort he closes his mouth as he tries not to feel so profoundly sceptical. "Something you failed to notice?"

Sherlock shrugs, unwilling to let go of the notion that there must be a rational explanation for what has occurred. "You were a soldier. You still possess a soldier's instincts."

John laughs. It's a harsh sound, a shocked sound, and he sobers quickly. "I didn't spot a tripwire at a dozen paces, if that's what you're suggesting."

He sighs. At other times, during other case, what Sherlock has suggested had been true. When he had decided that his war wasn't over and that only the battlefield had changed, he began to engage his surroundings differently and his heightened awareness had saved their skins more than once. But he'd never had the air thicken until it became an impassible barrier or had his heart tremble with such palpable dread. "I just knew." He signals Angelo for the bill. "And now, Sherlock, if it's all right with you, I'd like to go home now."

The cab ride back to Baker Street is filled with a contemplative silence. Sherlock leans back and shuts his eyes, retreating into his own thoughts. John stares out the window, watching without seeing the city pass them by.

Had his soldier's brain noticed some subliminal clue and put it together with other intangible bits and pieces? Had Sherlock or one of the witnesses they'd interviewed said something? Or was it information in the case notes they'd purloined from Scotland Yard?

He doesn't know. John closes his eyes in an imitation of Sherlock and tries to re-imagine himself as he'd been earlier. All he can recall is the empty street in front of him and Sherlock at his side as an unseen hand yanked sharply at his collar and whispered into his ear not to take another step if he valued their lives.

The hair on the back of his neck stands as he remembers that ghostly whisper. He knows that if he hadn't listened the evening's outcome would have been very different. He shivers, a body tremor intense enough to rouse Sherlock from his thoughts. "John?" There is a worried frown on Sherlock's face as he peers intensely into John's.

"Nothing," John says quickly. He gathers his coat closer around his frame. "A chill. That's all."

It's not a lie. He's cold to the bone. But it's not entirely the truth either. His world has suddenly become a more profound place, and the possibilities contained within it are overwhelming.

end