A/N: I have Asperger's Syndrome, and empathy is something I have real difficulty with, not only personally but also a lot of people are under the impression that no one with Asperger's can feel empathy, which is not true. So this is kind of my way to express what it's like in my head when empathy becomes an issue. Also, the last half of this story was inspired by the song 'Drifting' by Plumb, so if you want a really good song to listen to, that's one. Also, the story will probably make a lot more sense if you do. :P Just kidding, hopefully it'll make sense either way. Hopefully.

It wasn't always crime scenes that got him started on it; sometimes it was anything. A story on the news, an article in the paper. Something that bothered other people and stirred nothing within him beyond a dull shock. Sometimes there was no cause and it just happened, randomly, as if his mind were punishing him for its problems. This was one of those times, when his mind had nothing to do but turn inward and tear him to pieces. He turned abruptly and went down the stairs, out into the winter day where it was nearly freezing. He was in his shirtsleeves and didn't bring his coat, but the cold barely touched him; not the cold on the outside, at least.

He felt empathy. He really did, it wasn't just a pretense that he made to appear normal. He was capable of feeling affection for people, and feeling their pain. When he was a child he had asked his mother once if emotions were something you caught, like a cold or a baseball. She had laughed and explained to him that that was called empathy, and yes it was kind of like that but it wasn't so much catching them as it was realizing when someone was upset and feeling the same. When he was little, he had felt people's emotions sharply, like they were arrows launched at him from all directions, and he began to sink. He was in the ocean, with the tides and the waves and the wind pulling him in a thousand different directions, and it was too much for his mind to handle, but there was no one to stop him from drowning. So he had yelled and cried and tried to get away, but the people just kept coming, launching their invisible arrows. The ocean had gotten bigger, the tides more violent, until the balance tipped.

He felt the sudden emptiness more sharply than he felt the mass of emotions. Everything sucked away like water down a plug hole, the ocean behind a floodgate, and he was finally dry. But it was more than that. He was cold. The emptiness was all-consuming, destroying every feeling in its path, including his own. He could feel nothing, not even a twinge, no matter how hard he tried. Then, the floodwaters would recede, the gates open, and he was back in the ocean. The fight had been going on since he was little, the constant struggle between feeling too much and not feeling at all.

Most of the time, the struggle sat at the back of his mind, neither here nor there. But sometimes his mind would drag it up, when he had nothing to distract himself with, nothing to stop it. He moved, and he kept moving, to stop the ocean from consuming him again. In the ocean, he would give anything not to feel. In the cold, he would give anything to feel again. He took cases, he read books, anything to stop his own mind from attacking him.

When the cold came, it brought with it an absolute darkness, when he knew that the cold was wrong but he just didn't care; anything to get away from the waves. His mind shut down completely in an effort to stop it from being overwhelmed. It was like a system that had received too much stress and collapsed. There were times when he just couldn't feel anything, when he couldn't care about not caring, and those were the ones that scared him. That made him think, am I really a sociopath? Because what other explanation could there be? The part of his brain that the darkness spawned from hated him, told him that he was wrong and inhuman. Slowly but surely the rest of his brain followed, until he hated himself for what he became. A small voice in the back of his head whispered to him, wouldn't it be so much easier to just embrace the darkness? To stop caring, ever, and not look back? But he never did, because he wanted to come back. He didn't want to be overwhelmed, but he couldn't bear being hollow.

When he was trapped in the ocean, it didn't take long for him to start drowning. He fought to defend himself from the elements, and the fighting made him angry and frightened and he closed off to the world. All the emotions, all around him, everything went in but nothing came out. He didn't know how to let it out. He was cursed to feel empathy greater than most people, but never be capable of expressing it. His body went rigid and his mind went blank whenever he tried, and words froze on his tongue. The emotions remained locked inside him with no outlet. And so the feelings kept coming in, more and more and more, building up inside his head until he wanted to scream out loud.

He had walked all the way to the park without even realizing it and he stopped in front of the pond, shivering in the cold. The switch hadn't flipped yet, and the painful mix of emotions was at its crescendo, when his mind was tearing itself to pieces, killing him from the inside. He contemplated the near-frozen water in front of him, fighting the sudden urge to jump in, just to see what it felt like.

John came home late, thanks to the rush hour traffic, and hurried up the stairs. He wasn't entirely surprised when there was no sign of Sherlock; the man made a specialty of going out at odd hours, and even though they'd had no case, he was probably looking for some borderline illegal part for an experiment. He was about to toss his jacket on the couch when he caught sight of Sherlock's coat by the door. He called out for the taller man, and became nervous when he got no answer. He went downstairs and asked Mrs. Hudson if she'd seen him. She hadn't, but she'd heard him go out about thirty minutes ago. John frowned and ran back upstairs.

He seized Sherlock's coat and tossed it over his arm, now seriously worried. It took him twenty minutes to track Sherlock down, standing in front of the pond, head bowed. John ran over to him, pulling the coat out as he went.

"Bloody hell, Sherlock, it's almost freezing out here, why didn't you put your coat on?" Sherlock shrugged but didn't respond, still staring at the icy water. John looked at him and realized in an instant what he wanted to do. "Don't. Please, don't." Sherlock turned his gaze on John, and John felt a stab in his chest at the pained look in his eyes.

"Why not?" It killed John to see his friend like that, not even sure whether life was worth living.

"Because whatever it is, it'll get better. I promise. And also because I would pull you out again." John put Sherlock's coat over the taller man's rigid shoulders and sat down on the grass, ignoring the temperature. Eventually Sherlock joined him, slipping his arms into the coat sleeves and resting his forehead on his knees. It took fifteen minutes for him to say anything, and when he did, his words were halting and unsure.

"I feel things. Empathy."

"I know. I never bought that whole sociopath bit."

"I feel it too much. All the time, from everywhere, it's like drowning. I can't get away from it, and I can't let it out." John thought about how infrequently Sherlock expressed any type of emotion, and thought about what it must feel like to receive everything and never be able to release it. The thought caused another stab in his chest, and he sighed sadly. He didn't know what to tell his friend, except that it would be okay eventually, which was something he couldn't guarantee. He put his arm around the detective's shoulders.

"I know I can't stop the water from coming. But I'm not going to let you drown." Sherlock's rigid shoulders began to relax infinitesimally. The men spent the next twenty minutes sitting on the nearly frozen ground in front of the duck pond, not saying a word. Finally, the tension in Sherlock's muscles eased and he sat up straight. He stared ahead for a couple more seconds then turned to John with the slightest shadow of a smile.

"Are you ready to go?"

"Yeah. I don't know about you, but I'm getting so cold I can't feel my hands. Are you ready to go back?" Sherlock nodded. He was still in the ocean same as ever, but the cold hadn't come, not this time. This time he hadn't drowned. It wasn't over for good, of course, the fight that had begun in childhood. Maybe in a day, or a week, or a month, the battle would begin anew. But it was over for now.