Disclaimer: I do not own Sherlock Holmes, nor any of the characters from that TV series or books mentioned.
After John had retreated to his room, Sherlock strode over to his desk and flipped his laptop open. He opened his browser and looked up John Watson. He hadn't done this before, as he thought he knew everything he needed to about his blogger. Newspaper articles, blogs, even fanpages came up, but they were all about the both of them, Holmes and Watson. Sherlock bookmarked a few to critique later and maybe to try and make John laugh. After finding some that he thought might earn a chuckle, Sherlock continued with his mission.
Skipping a few pages of results, he was able to find the start of John's military time. "Soldier captured, MIA," "Search for Watson Unsuccessful," "John Watson Found in Enemy Camp," "Soldier Returned Home," and many other articles detailed the story of brave soldier Watson, a very different man than the one Sherlock knew. The pictures showed a hardened warrior, dust smeared across his face, and a pair of circular dog tags hanging from his neck. Sherlock drew up an image in his mind of his John, a smiling, softened doctor who wears collared shirts and thick sweaters. He didn't think either man would have recognized the other. Side by side, they were two different people, one rough and eager, the other more controlled and patient.
There was another photo, on an article about John's return. It must have been just after he had gotten back. It wasn't official, but Sherlock thought, perhaps taken by his sister or a girlfriend. He was sitting in a dark red chair, wearing a gray t-shirt that looked out of place on John, but hugged his still toned muscles. The walking cane he had used when Sherlock had first met him leaned against his leg and he was smiling one of his John smiles, crooked and slightly open, as if he'd just seen the most wondrous thing. Sherlock remembered the first time John had looked at him like that.
It had been at Angelo's during their first case, the one John so ridiculously named "A Study in Pink." Sherlock had glanced over to see if John was losing interest in him and instead saw this incredulous grin. For a brief moment, his mind had gone blank and that smile was taken and catalogued and put into a room in his mind palace. Each smile after that had been put into the same room along with each hideous jumper and each crime scene compliment. There was a John room in Sherlock's mind palace and he had never once thought of deleting it to make room for more important things because there wasn't anything with more value to him.
Sherlock scoffed at his own thoughts. Sentiment, he reminded himself, is a trait found on the losing side. Even so, he couldn't stop himself from smiling to himself. Part of him was a little hurt that John didn't want to solve as many cases with him, but Sherlock knew he was being selfish and shouldn't blame John because who would, after all that man had been through? An image of John's torso flashed in Sherlock's mind and he shuddered to think of the pain he had endured.
The usual mutters began from John's room, but this time Sherlock couldn't ignore them. There was something about their pleading nature that tugged at him. Sighing, and rising to his feet, he walked over to the room much like the first time this had happened. He cracked the door, expecting a gun to the face, but was instead greeted with John slowly lifting his head. His eyes were rimmed with red and his face a dusty ashen color.
John stood and walked over, his steps forceful on the wooden floor. He jammed his finger into Sherlock's chest and pushed him against the wall. "J-John?" Sherlock asked tentatively, confused and more than a little frightened.
"You did this to me, you filthy bastard." John spat, specks of saliva hitting Sherlock in the face.
"Did what?" His voice shook and his hands trembled at his sides. John was thrown back to the ground as if shot, a red stain spreading from his left shoulder. As Sherlock watched in horror, more stains began spreading, blood seeping from scratches all over John's body. His white cotton shirt grew crimson and John lay on the floor, choking on his own blood.
"You did this to me." John coughed out. Sherlock dropped to his knees beside John, trying to stop the bleeding. His eyesight was blurred by tears he didn't even know were forming. Wherever Sherlock touched, scarlet followed, his fingertips doing as much damage as the sharpest knife. And John just laid there, his once clear blue eyes growing dimmer.
Sherlock sobbed, his hands frantically flying around John's chest, still trying to hold the wounds shut. He cried out to Mrs. Hudson for help, for Lestrade, for Molly. He needed someone to help him, to take care of John, to save him. But no one came, and John's head thumped to the ground, the life drained from his eyes and body.
Sherlock woke with a start, nearly toppling out of his chair. He glanced at his hands, expecting to see them drenched in the blood of his roommate. Instead, the pale slender fingers stared accusingly back at him. He couldn't get the image of John out of his mind, the way he had told him it was his fault. It was true; Sherlock had invited John into the world of crime and murder. John had followed and Sherlock hadn't given it a second thought.
Glancing at his computer screen, the laughing eyes of saved soldier John Watson stared back. This time Sherlock could see the dark shadows in them, the sleepless nights and the hollow soul. Touching his cheeks, Sherlock realized he was crying. Whether it was left over from the dream or from the realization that he no longer knew his best friend, Sherlock wasn't sure.
He slammed shut the laptop and went into the kitchen to brew a cup of tea, but his hands were shaking too much, so he just sat in his chair. His fingers drummed on the arms and he needed something to do. He returned to the kitchen and opened a cabinet above the fridge that was too high for either John or Mrs. Hudson to reach. Sherlock pulled out a small jar with a plastic bag in it. Inside the plastic bag was a surprisingly large amount of heroin, a fine white powder.
Sherlock didn't have the time or the patience to boil and inject, so he tapped out a line and snorted it off the counter. He knew he was wasting it, but when he felt the effects settling in, his muscles relaxed and he willingly let himself be taken into the familiar and comfortable embrace of the drug. He replaced the jar and returned to his chair in the living room, already disregarding his dream. Sherlock let himself drift off into a dream like state and realized he didn't care if John found him high tomorrow.