Sherlock took a cab to the shore of the Thames where he and John once examined a museum guard who had been killed by the assassin The Golem.

Melodramatic names for killers seemed to be a significant part of Sherlock's life right now.

He still was unsure what he was actually feeling at the moment. About anything. The thought of leaving John behind left him strangely numb.

And he still hadn't called Scotland Yard. He knew he wouldn't though. He wasn't so numb that he was unaware of his own intentions.

What would he find when he met The Surgeon? Could all of his wild fantasies be anything like the truth?

Well, he was soon to find out.

He got out and paid the cabbie far too much. It didn't matter to him now.

He walked down to the waterline and saw a figure in the distance.

There he was. Like he said he would be. And seemingly alone, at that.

He hadn't noticed Sherlock yet. He could still call the Yard and just get this psychopath arrested. It would be easy.

He didn't even reach for his mobile.

He took a few steps. A few more.

He was a little surprised that the man that was obviously a genius hadn't noticed him yet. He wasn't sneaking, after all. Maybe his perceptions weren't so impressive in person.

Maybe he in general wasn't as impressive as Sherlock had always figured.

Could whoever this was really stand up against John? John, the one who always understood him? The only one who had accepted him for everything that he was?

Was Sherlock making a mistake?

That was when the man seemed to notice him. He turned—

Sherlock blinked. And did it again. And a third time.

His first thought, his very first, was that he couldn't believe this was happening again. The pool. Where Sherlock had been expecting a killer and saw John instead. And then realized a bomb was strapped to him, but for half a moment, he thought John really was the killer.

But this time, he made the assumptions in the opposite order. Oh, The Surgeon took John. Original.

But then he looked at John's face. Even in the gathering dark, he didn't look particularly frightened. Or upset. Maybe he looked a little smug.

"John?" Sherlock managed to choke out.

John stepped forward. "I really wondered if you had figured me out, and you were just humouring me. But from the look on your face, I was wrong there."

Sherlock didn't know what to think—maybe for the first time in his life.

Sherlock, suddenly, had a very late deduction. He remembered every time he got a text from The Surgeon, John was either not in the room or had been on his phone only moments before.

John was the one who found the note in his own bedroom.

John's DNA being the only thing he could find after the break-in.

John was a doctor, the only doctor in the UK Sherlock hadn't looked into as a suspect.

John…

Before Sherlock could think of a single thing to say, John was speaking.

"I'm sorry about how much this has all put you through. You're so stubborn, I didn't see any other way."

Sherlock didn't hear it, not really. He was still trying to think straight. To understand.

"How?" Sherlock finally asked.

Part of Sherlock was embarrassed. He adored John, but John was no genius. How did Sherlock not manage to figure John's plan out when he was 1) pretty ordinary and 2) living in his flat?

John stepped towards Sherlock. "Who in the world knows you better than me? Who has seen your methods over and over and knows exactly what you look for? And so, who's the most likely to be able to trick you?"

Sherlock's mouth was flopping open and closed wordlessly.

"The ideas were mine, but I copied some of them. Anything that confused you in other cases, I did myself. And then I started the letters when I was afraid you were going to figure me out to distract you. I'm sorry to say, I'm no genius. I just know you, Sherlock. Better than you know yourself, sometimes. So anything I couldn't do myself, I paid someone to do for me. The funny thing is, I only was trying to fool you. You're the only one I know how to fool. If the Yard had a little less faith in you and looked into it themselves, with a different eye, they might have seen it. But they didn't, because they had you and knew that had to be better."

But the most important part of this whole thing was only just dawning on Sherlock.

This means that his virtuous, kind-hearted John… killed people.

And liked it.

John had killed before, but Sherlock had known his hesitation at ending a life. What had happened?

"How could you do it? Was this all to get my attention?"

John rolled his eyes, but had a kind of fond smile on his lips. "It's not all about you all the time, Sherlock. No, it wasn't about that, not at first. It was… I was mad. At everything in the world. I lost Mary and my baby and I hated everything for it. The first killing was an accident. That was true. And the feeling of it…. I liked it. I never thought I would, but I did. I found something that I'm inexplicably good at. And I like to think that killing those people did some other people some good. Even if some of them had only been wronging a single person, I saved them." John was quiet, watching Sherlock continue to flail. "Is The Surgeon boring now that you know he was me?"

"But…" Sherlock was able to mutter. "You didn't talk like you," he added lamely.

"It's not so hard to put on a character. Especially when it was only writing. I thought pretty hard about the way I phrased things. I had to stretch the truth once or twice, just so I didn't lose your attention."

Sherlock still couldn't believe this. He'd never been so confused before. John… John…

"Sherlock," John said, stepping forward again. He was close now. Too close. Not close enough? Sherlock didn't even know anymore. "Sherlock," John said again, and that's what made him meet John's eyes. Because it was that same voice. The voice John had when Sherlock—as rare an occasion as it was—was too bewildered to function. Or was feeling—also rare—insecure. That same loving, forgiving voice Sherlock had always adored from the start.

"So you started killing people," Sherlock whispered, "And all you needed to be infallible was me."

John smiled a warm smile. How could he still be warm, after all he'd done? After he'd found the demon inside of him and let it take him over? How could he still be good?

"No, Sherlock. I haven't been caught yet. I didn't need your help. No offense," he added with a smirk. But then he was serious again. "I didn't need you to be the perfect killer. I needed you because I love you, you daft madman." John had never said it before. Neither of them had ever plucked up the courage. Not until now.

"But… all the games. Why didn't you just tell me?"

"I had to be sure you wouldn't just turn me in."

"I still could have. I thought about it."

"But you didn't. Our correspondences were enough for you to see that you love this side of me too. And I love the dark side of you, the same as the light." Sherlock was blinking down at John. His John. "You always thought life in the light was dull. I know you did. So let's go."

"Where?"

"Anywhere."

"They'll know it's us if we vanish, won't they?" Sherlock asked.

"Come on, Sherlock. You know that isn't true. They'd never want to believe it was us, so they wouldn't believe it. And even if they did," John added, "We'd never be found."

Sherlock didn't know what his face was revealing, but John was getting more confident. He closed the distance between them and pressed his body against Sherlock's. "It'll be just you and me and whatever we want to do. No more control, no more chains. Freedom, Sherlock. And we can purge this stupid world of all the idiots that taint it."

It's funny how the dark side of John sounded strangely like something deep inside of Sherlock.

And Sherlock realized then that he could think about it for years and there were some things that wouldn't change.

One, he had always lusted for this type of thing.

Two, after this, things couldn't go back to the way they were. It was either stay together or be apart.

Three, John was right. Sherlock loved him. Everything about him. This too. If anything, this made them more similar than they had ever been.

"Just you and me," Sherlock repeated.

John grinned, and got on his toes to kiss him. It was soft at first, but then it changed. It was primal, harsh.

Everything Sherlock had been wanting and it was always right in front of him.

"I love you," Sherlock breathed.

"I know. Are you ready?"

Sherlock was scared, he had to admit. Leaving everything he knew. Being in a situation where someone else actually knew more than he did—John had been at this a while now. He was the expert of something for once.

Sherlock took John's hand.

And for the first time, the smile that John gave in return wasn't kind. Too much teeth, with brows and eyes that hinted at something much darker than joy. It was just a little bit… evil.

And the strangest part was that Sherlock didn't mind.

"I'm ready," Sherlock replied. "But John... you killed Moriarty. That's... I didn't think it was possible. How..."

John smirked over at him. "Ah, yes, Jim." Sherlock was surprised with the familiarity there. "He was the twelfth. It's a funny story, actually. But we have plenty of time for that. All the time in the world."

And they made their way into the darkness.

Thanks for reading. I hope you enjoyed. If you want horrible recounts of them murdering people, a detailed description of how exactly John killed Moriarty, or super kinky sex, I could make that happen, but I think this will do.