Warnings: Drug use, mild violence, a few swears.

Another fic written for a prompt on lj, asking for angst and h/c. Sherlock/John in a strong friendship/possibly pre-slash sense.

This is my longest fic ever, and my first serious attempt at angst, so feedback would be appreciated now more than ever. thank you, dears!

They never had a real fight before. Disagreements, yes. Fairly frequently, in fact. But never a real fight. It was bound to happen at some point, since they spent almost all their time together. Being with Sherlock would be a trial for even the most patient person, and John was far from a saint. Most of the time he was fairly tolerant. He was used to Sherlock's eccentricities. He put up with the violin playing and the disgusting experiments. He even put up with Sherlock's snide insults, since he knew that he really didn't mean it, most of the time.

But that night was different. It wasn't a disagreement over what case to take on or the merits of popular television. This was serious, and John couldn't let it slide. Even if Sherlock wasn't his best friend (which John was finally able to admit he was), the doctor in him simply couldn't overlook this.

Sherlock had come home high. John had figured out that he had once had a problem with cocaine. No one had ever explicitly said as much. In fact, the whole topic seemed to be taboo. But there were enough hints: Sherlock's reaction to Lestrade's fake drugs bust, a few snide remarks from Mycroft about Sherlock's "little problem," Sherlock's own silence about his recent past. John hadn't been sure which drug it had been, but it was obvious that Sherlock was a former junkie. But John had naively assumed that it was all in the past. Sherlock had his nicotine patches and his cases to keep him busy, and John never even considered that he might relapse.

He wondered what had caused it. Had something happened to drive Sherlock to it? Stress? Depression? Maybe just plain old boredom? The excitement of doing something wrong? With Sherlock it could be any combination of things that John would simply never understand.

But the why didn't really matter right now. He could tell he was high the moment he walked in the door. In Afghanistan some of the soldiers had developed habits to numb themselves from the stress of war. Narcotics had been cheaply available on the black market, and they had given into the temptation of dulling the pain of daily life. John had learned to spot the signs. He had learned how to deal with the men tactfully, to be non-confrontational, to convince them that they needed help. He had been thoroughly trained to deal with this.

But when he saw Sherlock waltz into the flat at 2am, his pupils wide and darting about manically, he had snapped. He forgot all the tactful phrases and persuasive arguments he had been taught. All he saw was a stupid man, a man he cared about, hurting himself for god-knows-what reason, and it made him angry. Furious, in fact. Furious that Sherlock would go and do something like this that could put their work, their carefully-crafted life together, in jeopardy. This was all John had, this flat, this job, this friend, and Sherlock seemed determined to mess all that up for a fleeting high.

But it also made him feel helpless. The same way he felt helpless every time he got a call at 3am telling him Harry had passed out or had been admitted to the hospital to have her stomach pumped, again. Every time she did something reckless and he couldn't make her stop, couldn't make her see how much she was hurting not only herself but John and Clara and everyone else who cared for her. It was selfish, and it was stupid, and all John could do was stand aside and wonder when the other shoe would finally drop.

So John had gotten angry, and Sherlock had gotten defensive.

"What the hell is wrong with you?" John knew he sounded belligerent, but he didn't care. He had cornered Sherlock in the kitchen where he was attempting to distract himself, fiddling around with something or other. Sherlock had tried to ignore him when he came in, to avoid eye contact and pretend everything was normal, but John wasn't going to back down, not this time.

Sherlock finally wheeled to face him. "What is wrong with me? Nothing is wrong with me, John, except that you insist on yelling in my ear at some ungodly hour while I am clearly busy. What do you want?"

John practically snarled. "You know exactly what. What the hell are you doing, coming home like this? You told me you were clean!"

Sherlock's mock-annoyed expression sobered instantly and he surveyed John with cool eyes.

"I believe what I do with my body is none of your business, John. You are just here to help pay the rent, remember? You may be a doctor, but you are not my doctor, and you have no right to stick your nose into my business." His tone was calm and even but ice cold.

"You're business? Fine, I'm not your doctor, but who gives a bloody fuck, Sherlock! I'm your friend, you idiot. What you do effects me too, can't you see that? Or do you find it so hard to comprehend that I might care for a cold bastard like you?"

Sherlock's anger ran cooler than John's, ice as opposed to fire. But it was no less stinging.

"Did I ask you to care for me? Did I ask you to barge into my life and turn things upside down? To become my bloody nanny? No, I don't believe I did. There are still things that are my business, and my business alone, and if you can't grasp that concept with your pathetic little brain then maybe you should get out."

Those words stung, hitting too close to buried fears John didn't want to consider. So he lashed back in kind. "Fine, maybe I will! Who wants to live with you anyway? You were right, you know: you aren't a hero. Oh no, not you. You're just a pathetic junkie, a sad, lonely man who's useless without his stupid drugs—"

And then Sherlock punched him. The blow came out of nowhere, hitting John just under the left eye, missing breaking his nose by mere centimeters. The impact sent John reeling backwards. His cheek felt like it was on fire, and he could feel the skin around his eye swelling already. His head was aching and he could barely think straight.

He hadn't seen it coming. But he hadn't been looking for it. He never would have expected it, not in a million years. Not in all the time he had known Sherlock did he ever imagine that the other man might hurt him. Not physically, and not on purpose. The others might call him a psychopath, but John knew better. He knew that Sherlock would never intentionally hurt someone, for all his cold bravado.

But he had. He had hit John deliberately, and he had hit him hard. He had been aiming to hurt, to cause damage. John couldn't feel anything but shock. Maybe anger would set in later, but right now he couldn't process what had just happened. He lifted his fingers to his face, to confirm what he felt, to make sure it was real. But there was the indisputable evidence.

Sherlock looked taken aback, as shocked as if he had been the one struck. He was staring at John with wide eyes, his dilated pupils making him look strange and alien. He was watching the mark he had left, which was quickly swelling and turning an angry red. His gaze was part detached fascination at the spectacle before him, and part horror at his own complicity in creating the blossoming wound.

He reached forward with tentative fingers, to touch it as John was. But John smacked his hand away. The anger that had been held back by shock was boiling to the surface now, and Sherlock's expression was making it worse. He looked surprised, curious, but not sorry. Apparently that was too much to expect from him.

That smack seemed to knock Sherlock out of his stupor. His eyes snapped back into focus, some of their usual sharpness returning, like a spell had been broken, like he was finally looking at John standing before him, finally registering the situation.

"Oh god. John." His voice was weak, quiet. It was a tone John had never heard from him before. But even if Sherlock was feeling sorry now, John didn't want to deal with it. His face was beginning to throb, and he had to get some ice on it quickly.

He turned to the kitchen and grabbed a towel off the counter, hoping against reason that it was clean. He filled it with ice and wrapped it into a makeshift bundle. Sherlock had followed behind silently, watching him, seeming unsure of what to do. John didn't care. He turned to the door to go up the stairs to his room, to nurse his wound and take some pain killers and maybe try to get some sleep, though it was doubtful with all the emotions roiling in his gut. But he couldn't stay here, couldn't stay around him. He didn't know what he might say, but he was damn sure it wouldn't be anything constructive. He just wanted to be alone.

"John." The voice calling after him was feeble, uncertain. But he ignored it. "John, I'm..." John paused, thinking maybe an apology was coming. It was too late now, of course, but it wouldn't hurt. It's not like he could make the situation worse than it was, after all. But nothing more came. Sherlock trailed off and remained silent, staring at John's retreating back. John sighed and shook his head, continuing up the stairs.

"Just, don't bother," he mumbled, unsure if Sherlock could even hear him. Then again, maybe he meant it for himself.

Surprisingly, John did manage to get some sleep. He had taken a strong pain killer, and it had been enough to knock out his stressed, over-taxed body. He slept deeply for a few blissful, dreamless hours, but still woke up at dawn by force of habit. For a few peaceful moments he could pretend nothing had happened, that today was like any other day. He could pretend that everything hadn't changed.

But it didn't last long. Soon enough the throbbing below his eye reminded him exactly what had happened the night before. He remembered it all, in unforgiving detail.

For the first time since he had moved here, since his life had changed, he just didn't want to get out of bed, didn't want to face the day. It was like his early days being back home from the war. There was just too much to face, and none of it pleasant. It would be so much easier to fall back asleep and let it all disappear. He still had a full bottle of pain killers prescribed for his shoulder. With those he wouldn't have to feel anything, could sleep without dreaming…

But he couldn't give in, because he knew the dark road those feelings led down. He'd been there before, and he'd seen other men give up. And that just wasn't in his nature.

Beside, this was nothing like being shot in the shoulder and invalided home. Compared to that trial this was nothing. It was just an argument between friends. People had them all the time.

But why did this feel so much worse? John couldn't quite place it, but something felt irreparably broken. He felt like something had been lost that could never be replaced. His chest hurt much more than his cheek. It was downright oppressive.

But the day had to go on. He got up and pulled on his robe and shuffled down the stairs to make his tea. Best to start off with the simple things and work from there. At least he could make his breakfast, and that would be as it always was. Something mundane to keep him grounded firmly in reality, to keep his mind from wandering off in a million unpleasant directions.

When he came downstairs he didn't see Sherlock in any of his usual spots, perched in his chair or hovering over the kitchen table. The door to his bedroom was closed and the lights were off. John highly doubted he was sleeping, if he was even in there. Not only did Sherlock rarely sleep normally, but the drugs still in his system certainly would have kept him awake.

He tried not to think of where Sherlock might have gone off to while he put the water on to boil and laid out the milk. He wouldn't let himself think of Sherlock out looking for another score, absolutely refused to imagine him injured or helpless somewhere…

Pointless. He could think of nothing else. Where the hell was he? For a brief moment John considered calling Lestrade, or even Mycroft, but he didn't want to have to explain to them how this whole situation had started. Especially not to a detective.

He had just sat down at the table when he heard the front door close, followed by footsteps on the stairs. He felt a flood of relief, quickly crowded out by apprehension. Now that he was sure Sherlock was safe his former anger and doubt were resurfacing.

The footsteps were slower than usual, hesitant, maybe. The door opened carefully, quietly, and Sherlock entered the living room. He looked like hell, John noted mildly. Even though he rarely slept, he usually didn't look like it. But this morning he looked like he hadn't slept in weeks, with bags under his eyes and hair a tangled mess. Maybe John's imagination hadn't been too far off. But one thing he did look was sober. John could see it in his eyes. That at least was reassuring.

Sherlock entered the kitchen and stopped short, surprised to find John sitting there silently, watching him. They stared at each other blankly for a moment, until Sherlock looked away first, his eyes dropping to the floor. He cleared his throat and stepped into the kitchen, heading for the refrigerator.

"I, uh, did the shopping," he mumbled, holding up a plastic bag as evidence. John gave no sign of reaction as Sherlock pulled out the items and placed them in the fridge haphazardly.

When he finished he turned back to John. He took the last two items from the bag and placed them on the table. Reusable ice packs. Something they probably should have owned a long time ago, given how often they got into scrapes.

"I thought these might be useful." His voice was quiet and thoughtful. He wouldn't look at John's face again, instead keeping his eyes trained safely on the table top.

John knew this was Sherlock's attempt at making things right, in some small way. But it wasn't enough, not this time. Normally he might let Sherlock's mistakes go with a convoluted apology or token gesture. But not now, not yet. This time required something more, something concrete, something lasting. But he also wouldn't be so childish as to ignore this obvious sign of truce. It was a start.

"I just made tea, would you like a cup?" John offered. The least he could do was act civil in return. Sherlock nodded eagerly, accepting this gesture as an offered opening. He sat down across the table and watched John carefully as he poured out the tea. He waited for John to sit back down before he began.

"John, I'm...I don't even know what to say." He was at a loss for words for possibly the first time ever.

"Well, you could start with 'sorry.' That's generally how these things go." He tried his best to keep the sarcasm out of his tone. He knew this was alien territory for Sherlock. And while he was still feeling resentful, he wouldn't purposely make this harder than it had to be, for both of them. It was worth something that Sherlock was even making the effort.

"Yes," Sherlock sighed, looking embarrassed."That. I'm sorry. I'm so sorry. I didn't mean..."

He gestured to John's face but couldn't quite bring himself to put his actions into words. But the evidence was there, he couldn't escape it.

"I didn't mean to hurt you. I would never. You know that...don't you?"

John paused to take a sip of his tea and consider.

"I never thought you would, no. But you did, Sherlock. And you know why."

He let the unspoken words hang in the air. They would have to finish the discussion that had ended so violently last night. Even if it hadn't been a big deal before, there was no way they could ignore it now.

"I don't do that anymore. I mean, I don't usually. Last night was a one-off, a stupid mistake. But I've stopped, I'm clean now. Mycroft made certain of that."

"But why, Sherlock, why now? That's what I can't understand. I don't care about your past, but this affects me too. Even if you don't want to acknowledge it, I care about you, and I care about what happens to you. And I don't want to see you make stupid mistakes."

"It only happened by chance, I swear. I happened to run into a man I used to know, who used to supply me. It was more for old time's sake than anything else. I considered declining, but there didn't seem to be much reason to."

"Not much reason to? Sherlock, you're a former addict. It's not like eating sweets, where you can have one every once in a while and no harm done. Once you start again you won't be able to stop."

"I can stop." Sherlock sounded like a child denying he had committed a minor misdeed.

"Sherlock." John looked him in the eye steadily, trying to assess what he found there. It was true, Sherlock did have more self-control than the average person. But he also had a propensity to become carried away and lose track of the world. Just one could easily turn into more, despite his best intentions.

"Sherlock, you can't do it on your own, you need to let me help you. Please. Not as your doctor, as your friend. Just let me in, that's all I'm asking."

Sherlock finally sighed and nodded his head, as if admitting surrender. "Alright. I will try my best, but if I feel that I need help, I will come to you. Is that acceptable?"

It was a difficult admission for Sherlock to make, and John wasn't going to push the issue for the time being. It was a step in the right direction, at least. He nodded his agreement.

But there was still something niggling at the back of his mind. He couldn't put all of this to rest just yet.

"Sherlock, I need to apologize too. I said some terrible things to you last night. But I didn't mean them, I didn't."

Sherlock gave him a tight smile. John knew he remembered every word just as clearly. It couldn't feel pleasant to recall them.

"Well, you may have been right about some things," he murmured, perhaps mostly to himself.

"No, Sherlock, I wasn't. I was just angry, and frustrated. But you know I don't think that about you."

Sherlock considered for a moment.

"You didn't mean any of it?" John shook his head in confirmation. "Not even the part where you said you were my friend, despite the fact that I am a 'cold bastard'?" John didn't miss the hint of a cheeky smile.

"Alright, some of it may have been true." He grinned in response.

Most of the tension seemed to have melted away. A few words couldn't fix everything, and things wouldn't be perfect after this. But then again, they never were, maybe less so for them than the rest of the world. But they were back on their usual footing now, back to their comfortable dynamic.

Sherlock resumed studying John's bruise, but with less hesitancy now.

"Let me see." Sherlock reached out a tentative hand, as if he expected John to smack it away again. When he encountered no resistance Sherlock leaned forward and touched the bruise gently. John let out a short hiss of pain and Sherlock pulled back, as if burned.

"It's alright," John reassured him, "just a bit tender. Be careful."

Sherlock resumed his inspection. The bruise was a deep purple and spread from the top of the cheekbone up to the underside of the eye. It would take a while to fade, maybe two weeks before it was gone completely, John had calculated. Sherlock's fingers were gentle as he traced the outlines and the contours of John's cheek, noting how out of place the bruise seemed, how wrong it felt. Actually touching it made it that much more real for Sherlock, and knowing he had put it there repulsed him deeply. But he forced himself to examine it, to memorize it so it could never be deleted, so he would always remember the consequences of what he had done.

John let him take his time. He seemed to need this, in some way John thought he could understand. He had gone through something similar as a child, the first time he had hurt Harry and his mother made him look at what he had done. He had never raised his fists to her again, even when she hit him.

Sherlock finally pulled away, as if coming out of a trance. He reached for one of the ice packs and broke the inner packet. He pressed it to John's eye and forced him to tip his head back, holding it firmly in place.

"You should keep this on intermittently for several hours, there is still some swelling," he instructed.

"Thank you, yes, but I am a doctor, you know," John interjected, but Sherlock just ignored him.

"Apply some moist heat to it later, to help dissipate any clotting."

"Yes, I know—"

"And take some extra aspirin throughout the day—"

"Yes, Sherlock I know." John cut him off firmly, taking hold of the ice pack and lowering his head. "I know what to do for a bruise. Army doctor, remember?"

"Oh. Yes." Sherlock looked a bit embarrassed at his own enthusiasm. "Yes, well, be sure to take care of it."

"I know, I will."

Sherlock stood and turned to head into his room. But he paused and turned back around. Swiftly, before John could even comprehend what was going on, he bent down and placed a soft kiss at the corner of the bruise, right below his eye. "I am sorry, John," he whispered. And then he was gone so quickly that John thought he may have imagined it. Lingering effects of the painkillers, maybe. He reached up to touch his cheek, but the dampness from the ice pack made it impossible to tell.

But either way, John felt better. He had woken up this morning feeling like the sky was about to fall down on top of them. But now he felt at peace. Things still weren't perfect, but in an odd way this incident had ended up strengthening their relationship. Sherlock would need help, but he would get through this. They would get through this. Together.

The bruise on John's cheek would last for two weeks. Two weeks to remind them of what they had come so close to losing, of what was at stake. Two weeks to work through their problems and come up with solutions. When John finally looked in the mirror and saw the last green tinge fading away he almost felt a bit sad. It was a mark that had started out as a reminder of failure and frailty and anger. But now he would remember it as the tangible symbol of how their friendship had grown stronger. Like a new sort of battle scar. The physical mark may be gone, but it's effects would linger far longer in their memories.