I own nothing but the plot, etc.
This is set after the Fall and has a lot of spoilers for season two. Also, this may be a first chapter or it may just be a story. I don't know where I'd go from here, so don't expect much.
It was a quiet day at 221B Baker Street. Sherlock was watching telly, yelling at the morons on the screen, and eating biscuits. John was on his laptop, typing out the story of their latest case, which had just ended earlier that day.
When the detective thought his friend wasn't looking, he'd sneak peeks at the blog post. He had missed this; they both had. This was their second case after the Reichenbach Fall (a story that John still hadn't been able to write out). When Sherlock revealed himself a month ago, they had fought. Or rather, John had screamed and punched his no-longer-dead friend in the face, and Sherlock had waited until his friend was calm enough to explain.
They had moved on. It was awkward enough at first, but they had easily fallen back into their old routine of nonverbal communication and constant light-hearted bickering. John was grateful that "you can never go home again" wasn't true for them; Sherlock didn't know there was anything special about it.
And here they were. Unwinding after a long case (Sherlock had about a day before the boredom set in again), sitting in an easy silence. Until it was broken by a knock on their door.
Sherlock frowned. "The outside door's locked," he said.
"Could be Mrs. Hudson," John replied, unconcerned.
"It's not." He stood and went to the door, listening, then turned back to John and lowered his voice. "Crying. Someone's crying."
John stood up quickly and went to the door, but Sherlock stopped him, motioning for the doctor to get his gun. John did so but didn't seem to think he needed it, and Sherlock opened the door.
Standing in front of them was a handsome brown-haired, wide-eyed little boy about three or four years old. He looked up at them, and there was hope in his eyes but also… fear. He was afraid and not just of something that had happened to him but of them specifically. Sherlock noticed that in the instant before John hid his gun and knelt down to speak to the child.
"What's wrong?" he asked. "Are you hurt?"
The boy glanced at him but then looked up at Sherlock again. Tears had cut trails through the dirt and dust on his face, and he was wearing a buttoned shirt that was meant for a grown man. But even with the round face and small, skinny body, Sherlock recognized him. Sherlock would always recognize him.
"John," he said quietly. "Move away."
His friend stared at him in confusion. "Why? Sherlock—"
"Look at him," the detective said, never breaking eye contact with the child. "Really look. It's him."
John looked back at the boy. "Who?" he asked, still uncertain but beginning to understand.
"Need… your help," the child said slowly, fighting with the words. "Sher – Share… Lock."
John stood up. "How do you—?"
"It's Jim," Sherlock said, saving him the trouble of figuring it out. He wanted to close the door in the psychopath's face, but… it was too interesting. "What happened to you?"
Jim concentrated, obviously annoyed at his own speech and undoubtedly clouded mind. "Emmies," he finally said, then shook his head. "Em – en – enmies."
"Enemies," John supplied.
Jim nodded gratefully. "Chase me," he said.
"Sherlock," John said, cutting him off. He opened the door wider and brought Jim inside. "Whatever's going on, he is a child. Possibly injured as well."
Jim shook his head. "No hurt," he said.
"Forgive me if I don't take your word for it."
The boy bristled, a dark look in his eyes. "'Till me, Johnny," he growled.
John paused, then nodded. "Yes, I can see that," he said.
"How?" Sherlock asked, studying the child with bright, interested eyes.
Jim began wandering around the room. "At… fall," he said, giving up on the word "Reichenbach." He found Sherlock's biscuits and took a handful. "The Fall. They found me." He shoved a whole one into his mouth.
"Who found you?"
Jim shrugged and ate another treat. "Wake up on th'street," he muttered. "Little. Hungry." He grabbed John's cold cup of tea and used it to swallow the dry biscuits.
"But what happened?" Sherlock demanded, angry. "How did you survive Reichenbach?"
Jim frowned, then mimicked putting the gun into his mouth with one hand. And started to cry.
"Aw, hell," John muttered. "Look what you did." He cautiously knelt in front of Jim. "James—"
The boy threw himself at John, who held him with a shocked expression on his face, trying to calm him down. Sherlock watched, fascinated, as Jim Moriarty sobbed into John's shoulder.
"What are we going to do with him?" John asked, keeping his voice low.
Jim was passed out on the couch after the meal the doctor had prepared for him. Sherlock sat in his favorite chair, hands clasped as if in prayer, and studied the child, his arch nemesis.
"We can't tell Mycroft," he said slowly. "He would lock him up somewhere."
"So?" John asked. At Sherlock's glance, he sighed. "Look, I don't want anyone to hurt him, but… Well, we certainly can't keep him."
Sherlock didn't respond, but John caught hastily covered idea in his expression.
"What? No. Sherlock, he's—"
"A brilliant mind in a child's body," Sherlock interrupted. His eyes were gleaming strangely. "He was a psychopath, but think about it. What if we raised him to be better? Nature vs. Nurture."
"He's a human being, not an experiment, Sherlock," John admonished.
"He's a murderer. Or he was. Don't you want to save his future victims?"
"Well…" He caught Sherlock's triumphant look; the detective thought he had one. "No! You don't care about them; you just want to test your theory! Besides, children need affection and kindness, not just food and education. Are you going to provide that?"
Sherlock waved a hand dismissively. "You know I don't handle sentiment," he said.
"Exactly. That's why—"
"That's what he'll have you for."
"What? No!" John sighed and then took a deep breath to calm himself. "What makes you think I'm going to agree to this?"
"Look at him," Sherlock said simply. The both looked at the sleeping child, a young Jim Moriarty. "Think what he could do with that brilliant mind. He's almost as clever as I am. In another ten or so years, if I raised his mind and you his emotions, he could be saving lives."
John hesitated. He's right, he thought. Jim could do great things. "You do realize that people will never shut up about us if we start raising a kid together," he said.
Sherlock could hear the defeat in his friend's voice, and he smirked. "Settled then," he said.
"Not settled," John snapped. "What will we tell them when they ask? Lestrade? Mycroft?"
"We'll tell them he's your nephew," he said. "Taken from Harry."
"No, no," John said, loathe to do that to his sister. "Godson. His parents are dead. That's the story."
Sherlock barely acknowledged the change, already slipping away into his Mind Palace, still staring at the little boy.
"You realize we'll have to devote our lives to this child, Sherlock," John said, trying to keep the detective's attention. "As in, every day, even if it is dull and boring. Food, baths, schooling… Are you listening to me?"
But he knew the answer. Sherlock had gone, leaving John alone with a sleeping little boy. He sighed, knowing that if they went through with this (and, really, there was no "if" when Sherlock made up his mind), this would be happening a lot. John would be left to deal with a child while the detective retreated.
It was going to be extremely difficult.
Jim sighed in his sleep, a worried frown twisting his handsome features. Without thinking, John reached down and smoothed the boy's hair in a comforting way. The former psychopathic killer settled and fell back into a deep sleep.
Maybe we can pull it off.