John

When you've spent most of your life dreaming of being a surgeon, then spent some time on the battlefield, then thrown some crime-fighting into the mix, being a GP in a small local clinic can seem incredibly dull.

Not that John Watson didn't like his job – you know, his real job, the one he was actually paid to do – but it did lack the thrill his adrenaline addiction made him yearn for. He was perfectly aware of how unhealthy it was, but it didn't stop him. It didn't help that it was mid-January, which only meant that his shoulder ached and that most of his patients consisted of cases of the flu or the common cold.

Mary was spending the evening at Molly's, those two having grown alarmingly close alarmingly fast, so John had decided to pay a visit to his ex-flatmate. He had a bit of trouble getting a cab, which only meant standing in the cold while his shoulder ached like nobody's business and he was shivering. When finally a cabbie took him, he actually thanked the man as if he was doing him a favour. This earned him a strange look in the rear-view mirror, but he didn't care.

Stepping into 221b now still felt like going back to your parents' house after you've moved out, and John couldn't help but enjoy the comforting familiarity of it. He went to greet Mrs. Hudson first, but she seemed to have gone out. John smiled to himself, thinking that she would be complaining about her hip when she came home. Upstairs Sherlock was playing his violin, though the sounds he was making didn't sound like Sherlock's usual work at all.

Frowning, John made his way up the seventeen steps, the familiar feeling of anticipation gripping him as he got closer and closer to the sound. Even when he was still living there, he would always dread that first step into the common rooms, wondering what might await him there.

But nothing seemed particularly out of place as John stepped into the living room. In fact, the flat even looked a little tidier than usual. "Finally cleaned up, huh?" he called, raising his voice to be heard above the sound of the violin. Sherlock stopped playing at once and turned to look at him, freezing as he took him in.

John groaned internally when he saw Sherlock's face. To the trained doctor's – and ex-flat mate's – eye, there was no mistaking the glassy eyes and the thin sheet of sweat on Sherlock's brow. It was all too clear. Sherlock had used again, and was in the middle of a trip.

Shaking his head, John debated yelling at him, but he decided to save it for later. Sherlock was obviously too far gone at this point, it would be a waste of time, energy and perfectly good swear words.

So instead he buried his cold hands in his pockets and asked, "Well, did you?"

The detective seemed to have a hard time focusing, and John watched his breathing closely, trying to estimate his pulse from a distance. "What?

Clean up," John enunciated slowly to get his point across, "Did you?"

Sherlock's whole attitude change and he grew dismissive as he went about putting his violin away. "Don't flatter yourself," he muttered. John wasn't entirely sure what he was supposed to make of that, but he knew better than to look for sense or reason in nonsensical, unreasonable behaviour.

Sherlock took a surprising amount of time straightening himself before turning to John and asking, as if fulfilling a boring chore, "Go on then, tell us how you did it."

Well this time, John was completely at a loss for what to say, but again he decided against asking. So instead he went to sit in what he still called his chair, replying with a dismissive "Later. I'm way more interested in what the hell is your problem.

I wasn't aware we had a new problem," Sherlock replied after he had sat himself down as well.

John was about to point out the fact that this was absolutely not a new problem, but then Sherlock asked something about John being a twin. For lack of a better answer, he said, "Twin? I thought it was never twins."

To which Sherlock replied with a question: "You're not going to tell me, are you?"

John was about to ask for clarification when he remembered Sherlock's prompting remark from earlier. Still having no idea how to reply to that, he simply held out his hands. "I really don't know what you're talking about, mate. Besides, that's not the point.

Oh, yes, our new problem. Do tell us all about it."

John hesitated for a second, wondering if Sherlock was really still playing into whatever scenario his foggy mind had cooked up for him, or if this was a sliver of clarity. He decided to try his luck. "Jesus, Sherlock," he sighed as he hunched over, placing his elbows on his knees, "How many times will I have to come back and find you high off your mind?"

Unable to stand his friend's glassy stare, John started to look around the room for the weapon of the crime. "Where did you put that damn thing?" he muttered mostly to himself. "Must be here…" he added before finally spotting the empty syringe on the floor, near the open door. He felt his shoulders sag in defeat as the reality of the situation stared him in the face.

"He's at work," Sherlock stated, and when John turned back to look at him he was surprised by the tension in his friend's demeanour.

"Who is, now?" he asked cautiously as he sat back, but he received no response. "What's the matter, Sherlock?" he asked, concern gripping his words, "Where did you go this time, mate?"

Sherlock's eyes suddenly drifted down to stare at John's jacket, widening in some sort of realisation. John had no idea what Sherlock's mind was seeing, but he had a feeling he didn't really want to know. As horror slowly twisted his friend's features, John sighed to himself.

It wasn't the first time John had walked in on Sherlock right after he'd shot up. Hell, he'd even walked in on him about to shoot up once. That time John had grabbed the syringe off him and stomped on it, which had ended up in a huge fight about Do you realise how expensive that thing is and Do you realise what you're doing to yourself, at the end of which each of them had sulked at the other.

John had known perfectly well that Sherlock could and would easily get another syringe, but at least he'd made his point. Plus, his anger issues – courtesy of PTSD – very often demanded a sacrifice, so it had been nice to have something to break without remorse for a change.

But there was no getting used to the sight of your friend virtually playing Russian roulette with a loaded syringe. Especially as a doctor and an army veteran who couldn't help but feel envy at Sherlock's health and constitution. Sometimes it felt like all his experience on the battlefield had ever got him was a constant pain in the shoulder and fucked-up immune system, while Sherlock never ever got sick.

John didn't wish for anything bad to happen to Sherlock, of course, but it seemed unfair to him that the detective could put his body through hell – starving it, exhausting it, and pumping it full of drugs – without consequences.

John was startled out of these thoughts by Sherlock's razor-sharp voice. "Where is he?"

So much for a moment of clarity. Sherlock was still deep, deep into his own mind, and apparently the view sucked. Aware of the necessity to tread lightly, John asked, "Where is who? You're not making any sense, mate." He felt something shift inside his jacket, some sort of tearing. He checked and saw that the seams of his inside pockets were slowly yielding under the weight of the – unloaded – gun he had stuffed in there.

John had no idea what was so horrifying about his jacket, but Sherlock kept staring at it like it was made of Semtex. The part of John's brain that often led him to laugh at inappropriate times juxtaposed Sherlock's reaction to that of Johnny Depp in Fear and Loathing in Las Vegas, when he was so stoned we became afraid of the wallpaper. The doctor had to bite his tongue to keep himself focused.

"Look, whatever you seem to think I did," he told Sherlock reasonably, "I promise I didn't. But Sherlock," he added as he set his gun down onto the coffee table, closer to himself so not to give Sherlock ideas, "What's with all the weird questions? What could I possibly have done that you couldn't figure out?"

Sherlock only grew more and more agitated, staring at the gun, so John decided to backpedal a bit. "It's beyond me," he said calmly, trying soothe his friends, "I just don't see why you do this. What goes through your mind. If only you knew how hard it is to see you like this. We all indulge in some level of self-destruction, I guess," he tried to joke when Sherlock finally looked up at him, "But this is insane, Sherlock.

I don't believe you," Sherlock said, his voice dangerously low. "If what you say is true, then there's no game, no puzzle, no riddle. What could you gain from this? What would your endgame be?"

And that's when John understood the look of fear in his friend's eyes. That's when he realised what, or rather who Sherlock was seeing instead of him. Meanwhile, the detective's breathing had started to come quicker than usual, and his eyes seemed even more unfocused.

Doctor's instincts kicking in, John went to examine his friend's features, hoping the proximity would also help him see the truth. "I am not Moriarty," he told him calmly but firmly, "I'm John, the guy who used to live here with you, Sherlock. You understand that?" But Sherlock didn't seem to. "I want to help you. If you'd just listen—"

But Sherlock wasn't listening. Not that he'd been listening before, John realised absently as Sherlock positively lunged at him. Before he knew it, he was on the ground, trying to protect himself from his best friend's assault. A sharp pain erupted in his chest as Sherlock kicked and kicked and suddenly John couldn't breathe, the wind knocked out of him as his ribs cracked. Cracked, not broken, he self-diagnosed, Thank God for small mercies.

He didn't get much time to recover as Sherlock decided to switch from feet to fists, and soon it was his head that John was trying to protect. "Sherlock!" he gasped, still out of breath, "Sherlock, stop it! It's me!"

Turning his face toward Sherlock had been a mistake, and soon John saw stars as he felt himself fall backward. He felts his left heel nudge something under the sofa. As he was trying to figure out what it was, he looked up and saw Sherlock turn slowly toward him, his gun in hand. John's heart leapt in his throat before he remembered that the gun wasn't loaded. But Sherlock didn't know that, did he?

Sending a silent thanks to his late father for forcing him to join the rugby team in secondary school, John tackled Sherlock to the ground and pinned him there, panting from the effort. "Listen to me!" he ordered, "I'm not Moriarty, it's just a hallucination. It's the drugs, nothing more." Sherlock kept wriggling, the jerking movements hurting John's ribs, but the doctor held on. "Sherlock, you have to fight it. I know you're in there somewhere, just—"

But John was interrupted when something hard and solid came into contact with his bad shoulder. Pain exploded as damaged nerve endings screamed and he lost his grip, another sharp punch catching him square in the jaw. He fell to the ground, aware of the very real danger his friend represented. He had seen the look in Sherlock's eyes while he was pinning him down, and it had terrified him. The taller man wouldn't stop at hurting him. He was out to kill him. The fact that he wasn't the person Sherlock saw didn't matter.

John didn't even have a chance to sit up before his skull was introduced to a world of pain. He tried to brace himself for the blow, but when it came it still made his head reel in pain. He blinked several times, all aches and sores in his body dulling out as everything started to turn dark. Some part of him wanted to give in, but John fought it. Of course he did. He was a soldier, after all. He didn't know what else to do.

A pair of hands wrapped around his throat, and John realised that this was it. He was going to die at the hands of his best friend, who would have to live with this for the rest of his life. He wasn't going to be around for his daughter's birth, or to accompany her through her life. He would never see Mary's smile again. These thoughts made him fight harder and he remembered his gun, one hand shooting out to reach for it, but Sherlock soon crushed that hope, too.

"Sherlock," he mouthed, "Please…"

As he felt his strength slip away from him, John wondered how Sherlock would cope with the fact that he'd just murdered him. It was his last conscious thought as he slowly fell into oblivion.