Warning! Spoilers for Hounds of Baskerville. Big 'uns. I pretty much give away the whole mystery.


It starts with the lights and the noise. John still knows perfectly well where he is. Where else would he be but in a spooky laboratory out of a zombie shoot 'em up game, chasing ghosts for Sherlock? But he can feel something shaking loose in the corners of his mind. Something familiar. For some reason it makes him think of nightmares. His pulse jumps but he's not sure why.

Or maybe he is, because that noise is hideous enough to give a bloke a stroke. What is this, some sort of sensory overload experiment? Crank up the lights and sound till some poor animal loses its mind and goes into neural collapse? John feels like he's about five minutes away from it, himself, and it's pissing him off. Studies about the varied and alarming psychological effects resulting from different pitches of sound flood his brain, but never mind, Watson, a few minutes won't kill you. Just leave. Maybe it's creeping him out but he's more likely to go deaf first than...what? He doesn't know. Vague childhood phobias roll over in the back of his mind. Closets lose their terror when you've seen first-hand what a botched beheading looks like.

Only when the door doesn't open...for a second he knows they did it. In the next second, he's got no idea who they are and he's clearly been watching too many suspense dramas. The power shutting down makes him jump, but—automatic timer, obviously, as Sherlock would say. It's a relief, frankly, to get the lights out of his eyes and that bloody racket gone, even if it's still clattering around in his head and. That. That's when his chest tightens.

He still knows where he is, in a dimly-lit knockoff of a Michael Crichton novel, but damned if that rattling doesn't remind him of gunfire in a hot zone, and the spots flooding his eyes are sun on the desert, burning his retinas, and

...why is his heart pounding like this? It's just a memory. Nothing to hurt him here. He has nightmares but he's never done flashbacks...

...he can't shake the feeling that someone is here. Someone turned those machines on and off. There're noises, the quiet noises of life trying to pass unnoticed, he knows he's not here alone...

No. No. Stop it, John, you're working yourself up like a kid. No one's here. Be methodical. It's a small room. Nowhere to hide. He'll just prove to himself that he's in here alone and the worst thing he's got to worry about is someone coming in and arresting him for trespassing...

...But when the monkey jumps him, it's not a monkey. It's a 13 year old boy with an empty carbine and a big fucking knife who'd tried to take his eyes in Gereshk, and then John is on his knees in his fatigues soaked with the blood of a boy who hasn't hit puberty yet, and he can't breathe can't get the nauseating scent of copper out of his nose and he is sobbing. Because he joined up to be a doctor, not to kill children.

It looks to be going swimmingly, at first, and Sherlock is tempted to give himself a pat on the back for thinking this up. John's reacting more drastically than he'd anticipated, but these things are hard to gauge when you've only got your own mind to go by and it's so different from everyone else's. Drugs do strange things to people, after all, and he should know.

And there now. He's running. Staying low to the ground, keeping to cover, scouting his angles. Excellent, frightened but not losing his mind, just as he was trained. Just like so many times when he's backed Sherlock up, and after their row about friendship last night, those memories do give him a bit of a warm glow inside.

Only, when Sherlock holds up the recording to the PA microphone, John doesn't turn in the right directions. He should be looking for a wolf-thing, but he's canvassing for multiple enemies.

Wait. Enemies?

Sherlock frowns and leans forward for a closer look at the video feed. Yes. There, he's looking up.

For snipers.

Oh. Hell.

When Sherlock gets the door open, John is holding a gun on him.

It's not really a gun, of course. It's his electric torch. But from the way John's hands are wrapped around it, he clearly believes otherwise. It's a strange thing to know that your friend is pointing a deadly weapon at you, even if only in his own head. Something deep inside Sherlock's chest curls into a painfully tight coil at the sight, but he can't spare thought for that just now. If John is this far gone, then he needs to be stopped before he gets in a position to do real damage to someone.

Sherlock holds out a reassuring hand, murmuring John's name and soothing nonsense, and steps slowly towards him the way he'd approach a high-strung horse.

John's finger twitches. Sherlock flinches.

It feels like he's just been gut-punched. It hurts, irrationally, because it's only an imaginary bullet. But John just shot him. In his mind, John just shot him, even if he thought Sherlock was someone else, and that hurts. For one eternal, horrible, stomach-churning second, Sherlock doesn't know what to do. Because John is dangerously strung out and prepared to become physically violent if approached, and because he just shot Sherlock.

Which is the second in which John drops the torch like it's just gone red-hot and collapses to the floor with a retching scream like his stomach has just turned itself inside out.

He is hyperventilating, trying to inhale and exhale and sob and speak all at the same time. His face…

…Suddenly the hound is not the most frightening thing Sherlock has ever seen. If he ever sees that look on John's face again, he will put a bullet in the head of whomever's responsible. Even if it's himself.

"What did I do?" John chokes. It doesn't sound like his voice; more like air tortured into the shape of words. He holds his hands up as though he's expecting them to be covered in blood. "Oh Christ. Oh Jesus."

In the face of this anguish, Sherlock can't move for a moment. He's not- He doesn't do- And then John sobs Sherlock's name, and he realizes. John thinks he's shot me.

He falls to his knees in a flurry of wool, inches from John, and is grabbing, pawing at him without consciously controlling his hands. "John. John. I'm okay. It's okay, John. I'm here. I'm here, John, look at me."

John does, more or less by default because he's getting manhandled every which way, but Sherlock sees the instant his eyes focus back onto reality. Onto Sherlock's face.

And then it's John doing the pawing, John's voice cracking, splintering in a way Sherlock has never heard it do. "Oh Christ, Sherlock, where, oh god, jesus god, please. I'm so sorry, I'm so sorry-" Searching for that invisible bullet hole, which he'll never find though Sherlock could point directly to it, and as Sherlock doesn't slump unconscious from blood loss or shock before his eyes, the rest of John dares to follow his eyes back into reality. "You're…you're, are you okay?"

Sherlock grabs his arms, hard enough to bruise. Hard enough to reassure. "I'm fine. You were hallucinating, John. You didn't have a gun. You didn't hurt anyone, least of all me." Not true in the strictest sense, but if anyone had ever deserved it…

This is not the place to put John back together. Sherlock keeps muttering to him, gentle words, he doesn't even know what he's saying, and he bundles John up against him and gets him out of this godforsaken place.

The next morning finds them in the charming yard of the charming inn, drinking coffee in the thin gauzy dawn of early spring.

"You were wrong, it wasn't in the sugar. You got it wrong." John is right, of course, and if an admission is the price he wants for an apology, then Sherlock will pay and consider it a bargain.

If the drug wasn't in the sugar, then Sherlock didn't trigger John's flashback. Which means that, by all rights, it wasn't his fault. That should make him feel…if not all better, then at least substantially, but his heart still hurts where John shot him—aim perfect as always—and he can't deny he's earned this pain.

He rubs at it absently, even knowing it's futile. John's eyes flick down to follow the movement.

When John's hand comes up to rub at the same place on his own chest, Sherlock thinks he might bleed out of an imaginary wound. Because this is what he did to John when John pulled that trigger. That shadow in his murky blue eyes, Sherlock can name it now, after this week, because he feels it too. John has introduced him to guilt. It's a scar he's going to carry for a very long time.