I wrote this before the trailer dropped for season 4 today. In fact, I wrote this months ago, but didn't have any intentions of publishing it. However, with the release of the trailer, the idea behind this piece intrigued me even more. If you could let me know whether or not you'd like to see more from this story, please let me know. :) Thanks in advance.

Jim was a virus.

Jim Moriarty was a virus that crept its way through Sherlock's mind and corrupted every piece of data it came in contact with.

It corrupted and destroyed until Sherlock was left holding the needle and pushing sweet relief into his veins.

It was true that Sherlock had drugged himself up before arriving at the airport. He was confident in his skills of hiding his impairment from John and Mary. They'd never know. Mycroft would know, but he knew his brother wouldn't say anything. Sherlock was going to be on a plane for several hours. It would give him plenty of time to sober up.

Except that wasn't what happened.

He'd had a temporary break from reality when he'd received the news that Moriarty was back. He realized that now. It was a side effect of cocaine that he was familiar with. But breaking the news to John and to Mary that Sherlock was still an addict was by far the worst part of that day. After Sherlock had managed to get his footing and left the plane, he'd gotten into the car that had driven John and Mary here. He'd passed out again once he was inside, not even remembering John and Mary entering the vehicle.

He'd woken up in hospital, John sleeping on a sofa in the private room.

Sherlock had managed to slip out without waking John. He left a note that simply read: Sorry. SH

Sherlock had been bouncing from drug den to drug den ever since. Every time he shot up was an attempt to purge the virus from his system. Anything to try and get the virus out of his head. Anything to get his thoughts back to normal.

So far, Sherlock had been successful in hiding from Mycroft or the Yard or whoever else was looking for him. He doubted John was. Mary's due date was approaching. John would be monitoring Mary, making sure she stayed comfortable. He wouldn't be out looking for him.

It had been four months since Moriarty's face had appeared on every screen in the country when Sherlock was lying on a sofa in a dark basement. He'd just shot up and was simply staring at the ceiling. He was thinking. Trying to find every instance of the virus that was infecting him and throwing it out. It was a process he had gone through several times before… more than several in fact, but never seemed to work. He didn't know how else he was supposed to get rid of the man from his mind. If Jim really was back, he had to get rid of this virus in order to think properly. In order to play the game correctly so that he'd be able to get to the criminal mastermind.

Sherlock's eyes shot open as he heard the front door upstairs slam open and immediate shouts of warning from the police echo through the halls. His hands immediately went to cover his face. He cussed as he tried to get himself off the sofa. How had he managed to get caught in a drugs bust? He had just managed to pick himself up off the floor after rolling off the sofa when he felt himself being pinned down against the ground, hands cuffed behind his back.

When Sherlock was pulled to his feet he found himself face to face with none other than Sally Donovan. Sherlock was expecting a biting insult from her but she merely reached for the radio clipped to her jacket. "Get a hold of DI Lestrade. Tell him we found Holmes." She dropped the radio and fixed Sherlock with a stern look, but something was off.

"What is it?" Sherlock croaked, only standing because the officer who had cuffed him was holding him up.

"That's not my place to tell you." Sally answered before walking off.

Sherlock was escorted outside by the officer and placed inside of a police car. He leaned his head against the car window and waited…

Sherlock didn't remember passing out, but it felt as though two seconds later he was being pulled out of the police car and taken to processing. He passed through processing in a blur, his mind trying to figure out what could possibly be wrong. The only thing he remembered clearly was his mug shot being taken. He was sure the picture of him with long, greasy, matted hair; stubble covered face; and sunken cheeks would be plastered across the tabloids the next day.

Sherlock sat in his holding cell, knee bouncing up and down with anticipation. Mycroft would post his bail. He had to.

Hours passed. No bail was posted.

Eventually, someone stood in front of Sherlock's cell. Sherlock raised his head and found Lestrade standing in front of him. Sherlock hurriedly got to his feet. "What's happened?" he asked, hands gripping the bars of the cell.

Lestrade looked angry, but his expression soon faded to sympathy. "As much as I'd like to yell at you for being a bloody idiot…" He sighed and looked down at his feet, running a hand through his hair. "It's your brother."

Sherlock's brow furrowed together. "M-Mycroft?" escaped his lips before he could stop it.

Lestrade nodded. "I'm really sorry, Sherlock. Your brother took a heart attack two days ago. He's in hospital. Doctors say he has heart disease. They had to open him up and put some stents in."

Sherlock could see Lestrade's lips moving, but all he could hear was a ringing in his ears. He let go of the bars, taking a few steps back. Lestrade looked incredibly sympathetic, pitying almost. But Sherlock couldn't hear a word he was saying.

"I need to see him." Sherlock whispered. He looked up to meet Lestrade's eyes. "Please. I need to see him."

Lestrade sighed and shook his head. "I'm sorry, Sherlock, but I can't just let you out. Your bail needs to be posted."

"Get a hold of Anthea. Mycroft's assistant. She can sort it out… Please." Sherlock pleaded.

Lestrade shifted his weight uncomfortably before he nodded. "I'll see what I can do."

"Thank you." Sherlock said before collapsing back onto the floor, leaning back against the wall.

"There's something else you should know." Lestrade said, still standing at the cell, though he'd taken a step back. "Mary had her baby. Healthy little girl. Named her Ella Scott." Greg gave a small smile in Sherlock's direction before leaving.

Sherlock's hands went up to knot themselves in his hair. Without realizing, he began to cry.

What had he done?