Author's note: Late update because I went to an awesome concernt of my favourite band, so I can't really say I'm sorry. Hope you still enjoy it though!
After he had evaded Sherlock, he began to think.
It was obvious that Sherlock didn't want to play. And, regrettable as it was, it appeared he never would want to.
Therefore, he had to die. If Sherlock wasn't fun, he had to take control of his body and find someone who was. He might solve Sherlock's cases, he might build a new web, but first of all he had to find the spoilsport and get rid of him.
If there was no other way, he would alter his memories until there was nothing left of him, but good, old-fashioned murder would be enough, as far as he was concerned. Before Sherlock had some other silly idea to try and kill him. He might succeed, and then where were they? He'd be gone, and Sherlock would forever be the dull consulting detective he was. That was decidedly not good, as John would have said.
So, regrettably, he had to get rid of his erstwhile playmate.
He quickly went to the weapon's room. Sherlock was obviously convinced he had found a gun that would work on him. It was only fair that he should find something that worked as well. Remembering the first weapon Sherlock had tried to use on him, he decided against taking any of the guns on the shelves. He would go for something more reliable, and he turned around to look over the knives.
Sherlock had a beautiful knife collection. One in particular caught his eye, Eastern with a sharp blade and a golden handle beset with jewels. He took it in his hand and gently pierced one of his fingers. It bled.
It worked. Happily, he carried the knife out, prepared to use it on Sherlock.
He had to find him first. Sherlock had to have a base, somewhere he felt safe; in the outside world, it was 221B, here it would be more inconspicuous.
Hadn't he wondered why he had never found the memory of his first meeting with John? It would probably be in this room. Sherlock was sentimental like that. All the memories that made him feel safe and protected. Jim had never needed such memories. He'd very much lived in the present. But the rooms and rooms full of memories were enough proof that Sherlock didn't want to forget a single one of them. He would put up a room for those he considered especially worthy of protection. But where?
He could have looked for it, but it would have taken a lot of time, and he didn't know when John would get suspicious because he hadn't moved for hours even though they had a case and Mycroft would undoubtedly demand results soon.
So he would go to Sherlock's subconscious once more. He didn't fear to be sucked in anymore; he was stronger, he could hold himself together much better, he would no longer feel any temptation to give in. He would be able to find a trace of the room. He was confident. No matter how well Sherlock hid it, the subconscious would know, there would be a lead, a thread, maybe thin and deep, deep in the dark, but there would be.
The door was still where he remembered it. He knew the mind palace well at this point, although he would never know it quite as well as Sherlock – at least not until he'd spent several years there, which might happen after all once he had taken over.
He dived in and was immediately greeted by the hostile darkness that had tried to pull him under so many times and attempted it once more only to be simply ignored as he began hunting for the thread he needed.
He didn't know how long it took, but there it was. The tiniest thread, almost imperceptible, but there for those who knew to look for it. Sherlock would be angry. All his work and yet there was the evidence, openly lying about. True, in his subconscious, but still. Maybe the consulting detective would have done a better job if he hadn't been affected by the changes Jim had brought to his mind, maybe at the beginning he could have been more careful, hidden the path so well that no one would have been able to find it, but these times were long gone and Jim had only to follow the path.
He was mildly surprised to find himself in a corridor instead of directly in the room. Sherlock must have protected himself better than he had given him credit for. The room couldn't be far, however, and he soon spotted a small, unimportant-looking door in the shadows.
Sherlock, in a panic, using his older brother's tactic of making something important appear as unimportant as possible. The Ice Man would have been touched, probably.
He tried to open the door, but to no avail. Sherlock must have used every lock he could remember. He couldn't stay there forever. He would have to come out at some point.
Jim settled down to wait.
Sherlock could tell that Moriarty had come. He could feel it, could sense the air quiver with anticipation. Moriarty was waiting outside, like an animal for its prey. He wouldn't have to wait long.
This time, he couldn't miss. He had to shoot Moriarty as soon as he saw him, killing him instantly.
Moriarty might have been on either side of the door, or he could stand in front of it, just waiting. Not that it mattered; he didn't have the time to make a plan, he couldn't ambush him from outside because he had severed all connections.
He opened the door. Nothing.
Moriarty wanted him to leave the room, so he did.
He immediately realized Moriarty was hiding behind the open door, and turned around just in time to catch the consulting criminal as he attacked him, a knife in his hand. He recognized the knife. It had been used in a rather remarkable murder, which meant he had remembered it especially well.
It would be sharp enough to cut his throat.
He managed to evade the fatal cut, even though it slid over his forearm. He barely felt the burn as he tried to aim but was thwarted by Moriarty, who constantly tried to grab him and moved around so fast that it was impossible to shoot. He did what Moriarty had done before and hit him with the weapon, which at least lessened his grip on Sherlock. It did nothing else though; he didn't collapse, despite Sherlock having used all the force he could muster, and he wondered if it was possible to kill Moriarty at all.
If he was a manifestation of a mental illness, if Sherlock had been wrong when he had assumed he was sane, he couldn't be killed. One couldn't kill insanity. He would have to attempt to incapacitate him, lock him away and speak to John. But if he couldn't even knock him out, how was he supposed to bring him back to his cell?
They wrestled as Sherlock desperately tried to come up with a plan. The only one he could think of was impossible, but he had seen enough impossible things in the last few weeks to believe in anything.
He tried to split his consciousness. If he was insane, this might be the worst thing to do; but he had to warn John, he was struggling with either Moriarty or a mental illness that could potentially endanger every one he knew, and the doctor had to know.
There were still the restrictions that Moriarty had put on him, but he thought he could find his way around it. He could tell John he was mad; he could ask him to get help; he could demand –
He dodged the knife once more as he thought, I can demand that John kill me.
If he had to die, if someone had to kill him, he would prefer it be his best friend. John would deny his request at first, of course, but if he managed to make him understand the situation, he would act because he had to. He had been a soldier, he knew when to follow orders even if he didn't want to.
He could have tried to escape, but Moriarty was quick and strong; therefore he attempted to have a part of him stay here while another accessed his eyes, mouth and ears. He was dizzy and confused, but he pressed on.
He would never knew how he managed it, but even as he threw Moriarty to the ground once again and pulled the trigger, only for the consulting criminal to roll away just in time, he opened his eyes and groaned John's name, the split in his consciousness almost a physical pain.
The doctor ran into the living room, obviously shocked at Sherlock's appearance, and he managed to press out, hitting Moriarty's arm with the gun and managing to get the knife away from his throat, "Moriarty – Kill me".