So this is just a quick little one-shot that tumbled out of my brain a few months ago. It's been sitting in my computer for ages. Only now did I think to post it.

I didn't plan to write more than this, but I could see it turning into a longer AU—maybe show John and Sherlock in therapy, mending their relationship, and pretend The Lying Detective and The Final Problem never happened. If you guys want to see more of this one, then let me know and I'll chug out more when I have time. Otherwise, here you are. Enjoy!

Also, if you think this needs another read-through or a beta, let me know. I literally just posted it after skimming it for typos.

Sherlock had seen John angry. In fact, that was practically their way of life—before Mary, of course. Sherlock had a habit of doing things that John secretly tolerated and outwardly hated, and Sherlock had never seen any reason to change their dynamic. As far as he was concerned, John stuck around, acting as if he actually cared for his high-functioning sociopath friend, and Sherlock never pushed his luck.

Well, tried not to. And trying never went over well.

But this was different. Sherlock stood still, frozen to the ground, as John hunched over Mary's dead body, first grunting, then groaning, then practically screaming, his head hunched down so Sherlock couldn't read his face. Not that it would have mattered, anyway. Sherlock knew he was hopeless at comprehending human emotion, and now it was coming back to bite him. He had no idea how to help John. No idea.

Friends would offer support, wouldn't they? So why was Lestrade just standing there? Sort of looking at Sherlock like something was expected of him? Somehow, Sherlock's over-observant brain registered that Vivian Norbury had been taken away, but he couldn't care less. John was at his feet, falling apart.

Of course—that was it. Sherlock was, as John kept reminding him, his best friend—so he was the one who would be expected to intervene. Sherlock tentatively took a step forward, moving to set a hand on John's shoulder, when suddenly his friend looked up at him with a scowl so ferocious Sherlock snatched his hand back.

"Don't you dare," he growled. "You made a vow. You swore it!"

And because he was completely right, and because there was suddenly a tight pain in his chest, almost like something left over from the bullet wound—though of course that was impossible—Sherlock stepped backwards, stunned, uncomprehending. It was as if his entire world was crashing down around him. All the logic, all the barriers, all the walls he nurtured and protected and rebuilt and strengthened day after day as time went on—it was all crumbling, falling, crashing away, and he could feel something soft inside, something fragile and hidden, something even he had never dared explore, open itself up and—

He shook himself, taking one step back, then another. And another, and another, and another, because he had no idea what else to do. This was one day he had never prepared for. Contingency plans had always included John at his side. He knew, of course, there was a time before John, a time when he'd lived on his own and sentiment had been a foreign concept, but those days were long past, weren't they? And even though John wasn't living in 221B anymore, he was still always there when Sherlock needed him, still always a willing recruit when danger arose. Sherlock hadn't realized, until he was staring straight into the angry, betrayed, hateful eyes of the friend who had once stood at his side, just how much he had come to rely on John's presence. John had turned him into a better man, someone Sherlock could almost—almost—accept and admire, but it couldn't last long. No, of course Sherlock would make the ultimate mistake, fail in his duty, and John would leave him.

Sherlock had always known this would happen.

Mycroft and Lestrade glanced at him, one after the other, but neither made a move. John bent down over Mary, not seeming to care about the silent battle waging over his head. Sherlock was the first to break from his paralysis. Barely considering the tremor in his hands, he spun on his heel, the coat flaring dramatically, and made his exit.

He walked through the glass tunnel of the aquarium, barely registering the sharks that swam slowly over his head and around his sides, and somehow was reminded of Magnussen. Charles Augustus Magnussen. The man was dead, Sherlock had killed him himself (regardless of what the edited security footage claimed), but Sherlock still recalled that last mission he and John had embarked on. Before all the Mary business had come to a head. (When had he assumed her past wouldn't become a problem eventually? Stupid, stupid, Sherlock.) Right after he had come back from the drug den, come back to Janine (who had been worth his while, even if he hadn't really had the time or the reason to pursue such a thing), and he had told John all about Magnussen, the shark, the Napoleon of blackmail.

Why did it seem, as Sherlock walked down this path, sharks swimming over his head, that he had finally met his match with that disgusting devil?

No, Magnussen hadn't gotten to him, but this was still blackmail, wasn't it? It was still an inevitable dead end he had been forced to walk straight into because of none other than his own nature. He may not have been a very empathetic man, or even a very caring one—though since John came along, he tried, he really did—but he had made promises that he had always intended to keep. How was he supposed to know that Mary would jump in front of him and take that bullet? There was always a hole in every plan. When saving a life, one always accounted for every detail except for the victim. The victim was never considered, because she was supposed to be a damsel in distress, wasn't she? When you tried to protect someone, you mapped the movements of the killer, the tormentor, the bully, whoever was making the threat. Which was what he had done, confronting Vivian Norbury. Never could he have predicted Mary's actions. Ah, yes—her past, his promise, his conviction to keep the Watson family safe if only for John, always for John, was an impossible mix, and Sherlock had met his match.

But not with death, no. With emotion. And this was a far worse punishment. He would gladly have taken that bullet. Somehow, this was different from the fall—he had a feeling John would have been okay this time. Well, not okay, but at least he'd have Mary, and she could assure him that Sherlock died keeping his promise instead of faking his death and insisting he was a fake. It was all different this time through. And it would have meant he was out of commission for a reason. He had made that promise for one reason only, and that was so that John would always know he cared. There were very few things Sherlock understood about friendships, about human nature, but there was one thing he knew as a solid fact—no matter what blunders he was fated to make, no matter what snide comments would inevitably slip from his mouth and hurt someone, it would all be okay if he was at John's side in the best way possible. Because first and foremost, John was Sherlock's friend, his only friend in all the world if one didn't count Mrs. Hudson and Lestrade (why they stuck around was a mystery to Sherlock), and there was one thing Sherlock could do to warrant that devotion—he would be there. No matter what. No matter what it took.

Even if it took his death.

But no. He had to live, didn't he? He had to live, and bear John's hard looks and his betrayal and his anger. He'd have to stand there and watch as the only man who had ever cared for him, the man who had called him brilliant and amazing and had always been so bloody honest and had just plain been so sincere, withered away and refused his help because Mary's death was Sherlock's fault.

The pain returned in Sherlock's chest, and he rubbed at the scar from Mary's bullet, wondering if it could possibly be hurting again after all this time. Maybe he should see a doctor about it.

Then again, maybe he should see an entirely different sort of doctor.

"…I can only help you if you completely open yourself up to me."

"That's not really my style," Sherlock replied.

He had sought Ella out for two reasons. One, because she knew John. It was useless to ask her to talk about a client, he knew that, but she knew John and that…well, Sherlock really had no idea why that made any difference, but the pain in his chest was accompanied by a little bubble of hope at the very thought.

And two, because he really doubted any therapist could get him talking, but what harm could it really do? He'd lost everything that grounded him. Logic, cold, bare-faced logic, wasn't going to get him anywhere when John had basically pushed him away. Logic didn't work with normal people. It was why Sherlock normally didn't deal with normal people. But he didn't have a choice now.

So he would take the only avenue still worth taking. Even if it destroyed him. Because the spot where he stood now was bound to destroy him anyway.

"I need to know what to do," he said.

"Do?" the therapist asked.

"About John."

And he could see in her eyes that his task would not be an easy one. Probably John had already come to her; he had come to her after Sherlock was dead. She knew what was going on, from both sides of the equation. If anyone could help him, it was her.

But Sherlock would have to do the legwork. Legwork of an…entirely different…and more frightening variety. A variety Sherlock had never dared attempt before.