AN: Remind me to wipe my search history after I'm finished with this fanfiction. Here are some research gems from the writing of this chapter alone: chemical formula for cocaine, insufflation of cocaine, injection of cocaine, cocaine overdose, oral morphine, intravenous morphine, psychological effects of morphine, recreational use of morphine, anti-opiates, morphine overdose, Naloxone, oral Naloxone, intravenous Naloxone, Naloxone nasal spray.

That's not even all of them. My flatmates must think I'm a hell of a junkie.

John shook his head abruptly and closed his eyes again, but he felt no more relaxed than he had when he had snapped awake a moment ago. Waking up throughout the night was a routine matter, and had been even before the tour in Afghanistan, but then, Sherlock had the same problem. The thing is, when Sherlock couldn't sleep, he was loud: showers, violin, breaking glass, he would do whatever he found necessary to entertain himself. Yet for the last four hours there had been absolute silence, and what should have been a relief was decidedly unnerving.

He's just pouting.

Probably, but what if he wasn't? He sighed. Tick-tock tick-tock. He was wound too tightly to go back to sleep now anyway. Though it might be against his better judgment, it wasn't going to harm anything just to check. He dragged himself off the mattress and down the stairs. His stomach rumbled briefly as his bare feet crossed the sticky linoleum of the kitchen floor but he pointedly ignored it.

Now he faced a dilemma. Sherlock's door was locked. How could he knock on his flatmate's door in the middle of the night and inquire as to his well-being without sounding like he was after a cuddle? He had to get Sherlock to come to him. He edged out of the corridor and back to the kitchen and made an entirely unnecessary fuss with some crinkly packages. Waited. Nothing. He tried something louder, banged some pans around. Still nothing. Now he was growing legitimately concerned. Sherlock was a light sleeper, and in spite of his own habits, he routinely shouted at John for disturbing him. Deciding to risk it, he turned the corner back to the door and pounded on it matter-of-factly.

Still nothing.

"Sherlock!"

Silence.

"Sherlock, I dunno what you're doing, but open your door or I'm breaking it." He was overreacting, he knew it, but he couldn't help it, he didn't care. Something's wrong.

"Sherlock!" He slammed the door again with his palms, once more for good measure, then set his shoulder against it. This wasn't a deadbolt, just a flimsy interior lock, and he hardly had to shove for it to buckle with a loud snap, sending him skittering, off-balance, through the doorframe.

His heart stopped, and suddenly he couldn't draw breath. Fuck me for being right.

Sherlock was curled on the floor, pale as ice and convulsing slightly. His eyes were wide, glassy, and even in the flood of light from the door, his pupils were hardly visible, swallowed up by the blue of his irises.

John crossed the room in an instant and was on his knees. His trembling hand fumbled desperately for his friend's throat, searching for a pulse, but Sherlock seized violently at John's touch on his skin. John gripped his shoulders, trying holding him down, but not daring to risk laying him flat on his back for fear that he would choke.

It had to be an overdose. Not cocaine. Morphine, then, going by the pupil contraction and the seizure. Injected, going by the vivid purple track marks on his bare arm. John's hands shook. He had a hospital-grade OD kit in the stairway cupboard with activated charcoal, Naloxone, sedatives, anti-psychotics, he had brought it home almost as a joke, a hollow warning to Sherlock about his then long-dead habit. That kit seemed miles away now. It would only take him a few breathless seconds to get it, but that meant leaving the room.

"Sherlock," he panted, not even sure if his flatmate could hear him, "I have to get the Naloxone. I'm not leaving you, I'm not going anywhere, I just need the kit. Sherlock…"

He was suddenly very still. John squeezed his shoulders harder. "Sherlock!"

No no no no. He had stopped breathing. Christ.

With a frantic, panicked urgency, he pushed Sherlock flat on his back, turned up his chin, pinched his nose and pressed his mouth over Sherlock's unresponsive lips. He was frozen there for an impenetrable instant. He felt that he could hardly draw enough air to exhale, but he tried, tried fervently. He managed three shaky breaths. Knew it was supposed to be two and then chest compressions, but he couldn't remember the rhythm, was afraid that his breathing had been too shallow to matter, afraid to do it incorrectly. But he felt the rapid, uneven fluttering beneath Sherlock's ribs and tried anyway, tried to imagine a metronome, knowing that his heart could fail. God, he lamented, what kind of doctor are you? How can you not know how to do this? He's going to die, because you can't remember how to do the fucking chest compressions.

He had cradled Sherlock's head for another breath when finally he convulsed again, but not a seizure this time, a ragged, halting gasp. Overcome with relief, John's head dropped for a moment against Sherlock's, but he was displaced by the subsequent fit of violent coughing. He was even more hesitant to leave now, but he had to get the kit. He wasn't stable, he could stop breathing again, worse, go into full cardiac arrest. He needed the Naloxone injection immediately, but John felt somehow that his presence was keeping his friend alive, that if he tore his eyes away for so much as a second, he would return to find Sherlock cold and motionless. With a quick, binding half-embrace, John leapt to his feet and ran back through the kitchen to the stairwell.

Every motion, each step, the twist of the knob and the turn of the door was an agonizing eternity, no part of him could move fast enough to escape the scalding of his frustration. What was all this shit in the cupboard that he had to dig through? Why did they have all this? He flung cushions and blankets and cleaning supplies out of the way, groping blindly for the nylon packet. It seemed to be taking hours, and while he sat here fumbling around in the cupboard, Sherlock could be dying, could be gone already. He realised suddenly why he couldn't see properly and stopped, panting. He gathered up the crumpled sleeve of his pyjama shirt and wiped the tears from his eyes.

And there it was. He snatched it and skidded back to the bedroom. Sherlock was still there, still breathing, though rapidly.

He threw the kit to the floor near Sherlock's head, crouched and unzipped it loudly. He tipped out the charcoal – wouldn't be much use, he hadn't swallowed it - and dug for the anti-opiate. Having a syringe in his hands finally made him feel steady, feel like a professional. He tapped the vial, knocking any bubbles to the top, uncapped the syringe, punched the needle through the cap then drew up the plunger. Another tap, couldn't be too careful, bubbles could be dangerous, especially when he was in a state like this.

He lifted Sherlock's quivering arm, guiding it into the path of light from the hallway, and pressed his left thumb into his blue-tinted bicep, blocking the vein until it stood out sickeningly in the scarred bend of his elbow. He was careful, well-practiced, but he missed the vein twice; once slightly too far to the left, once straight through, in too deep. Sherlock's veins were very small, he wondered why the hell he had chosen to inject. It was morphine, for God's sake, he could have easily taken the pills and dispensed with the frustration and damage of the veins collapsing. He found the right place, finally, and pushed the plunger. He felt Sherlock tense slightly against him as the solution sank into his arm. It must burn. John didn't know, he had never needed it.

Thirty seconds to a minute before it took effect, he remembered. He pulled Sherlock's head onto his lap, careful to keep him rolled to one side, knowing that he may still vomit, and John wasn't keen on scraping his throat out. The silence between them weighed on him like the ocean in his ears as the seconds ticked by.

Fifteen seconds. He was waiting for something to happen. What? He knew Sherlock wouldn't suddenly jump to his feet, animated and back to his old self. So what was he waiting for?

Thirty seconds. Something should be happening right now, surely? There were signs he could check for, pulse, pupil dilation, body temperature, muscle rigidity, but he knew that all of that should stabilize, would stabilize. He was alive, after all, he was breathing, and he would almost certainly make it now that the injection was done with, but he wanted something to let him know that Sherlock was still there.

Forty-five seconds. Wake up. Come back, please. Don't leave me. His fingers were tangled in Sherlock's damp curls, afraid of letting him go.

One full minute. Agony.

Finally, at a minute and eighteen seconds, Sherlock's eyes drifted closed. His pained breathing was slow, but deep and steady. His hand twitched, then moved, crept up until his fingers brushed John's knee. Yes, it's me, Sherlock.

"Can you hear me?"

His brow furrowed and his lips parted slightly.

"You don't have to talk." His voice would be rough, cracked. It was the sort of thing that John knew would embarrass him far more than seizing on the floor.

He didn't, but his hand tapped John's leg again. Suddenly, he drew up his knees slightly and choked, heaving like he was going to be sick. He hadn't eaten today, so he was mercifully spared the indignity. John's fingers brushed gently through his hair until he relaxed again.

"Alright?" Hardly a whisper.

He nodded faintly.

"We're going to stay here on the floor for a moment," John explained, quietly but not quite calmly. He was trying to be Doctor Watson, but he was too overwhelmed by John for now. "When you feel well enough I'm going to bring you up onto your bed. I'll go back to my room – I'll be quick, I promise – and get my mobile to call you an ambulance. The Naloxone can cause withdrawal-like symptoms immediately and you need to be supervised – "

"John." His voice was barely a breath, warm on his thigh. "Stay here."

"I'm just going to go to my room, I'll be back. And I'll go with you to the hospital – " They wouldn't let him past the waiting room, he wasn't family, but still.

"No."

"Sherlock – "

"No, John." He took a few slow, urgently needed breaths. "You're my doctor."

John licked his lips as the blood pounded in his ears. This went against everything he knew; it was just about the least professional way to handle this situation, but it seemed better somehow. Better this way. Better that they were together. "Okay."