Mycroft had been a constant, if not always welcome, presence in Sherlock's life. Even in his physical absence, he occupied a prominent space in Sherlock's mind palace (to Sherlock's great dismay.) There he was, relentlessly mocking, lecturing, and making a general nuisance of himself. Hard as it was to admit, his advice had been helpful for some minor issues, such as saving his life when he was shot, and saving the day at John's wedding.

Sherlock denied that Mycroft's presence was any indication of any affection in their relationship. Why, Moriarty himself kept popping up in his internal residence, like a buzzing fly that kept returning to irritate you. It was not surprising, then, that his archenemy (Mycroft, of course, not Moriarty. Big brother was there first and would always be Enemy Number One.) was there too annoy him too.

When the Consultant Detective had drugged himself almost to the point of oblivion, his addled mind had constructed the most delightful image of his nemesis, exactly the way he should have been in reality, in his opinion. Mycroft was blown up nearly beyond recognition, and spent his days sitting on his enormous backside and stuffing himself with sweets. Sherlock had never really forgiven his brother for losing weight, thus denying the younger brother his favorite weapon to taunt the older one. (Not that Sherlock didn't try. His comments about the diet and weight had lost their sting, unfortunately.)

The overblown Mycroft and the Victorian-style detective had played the most delightful games. Sherlock would try to deduce the amount of time Big Brother had left, and Mycroft would try to decrease it by stuffing himself even more. Yet that Mycroft, while fat and lazy, still always got the better of Sherlock. He could solve all the cases without ever getting up from his seat, while Sherlock was left frustrated even after running around and exhausting himself. Nevertheless, Sherlock would swallow his distaste and always go to his brother for help. If there was one thing he was sure of, no matter the timeline or state of reality, it was that Mycroft would always help his little brother. Always.

That's exactly why Sherlock hadn't believed a single word of Mycroft's vile spewing. Based on the evidence he had accumulated over the years, Mycroft would never deliberately hurt his brother. He made mistakes, yes. He hurt him plenty, true, but only with the intention to help, no matter how twisted his intentions were. So why? Why was he insulting him in this manner, and urging him to shoot his best friend, an act that would totally destroy him if he ever agreed to it?

Oh. Oh. When you rule out the impossible, whatever remains, no matter how improbable, is the truth. (Thank you, Mycroft. Now get out of my head!) The irritating idiot was trying to get him to shoot Mycroft himself, not John Watson. And he wouldn't just ask politely, knowing Sherlock's tendency to do the exact opposite of whatever he asked. Reverse psychology might work on five year olds and some idiots, but not on Sherlock Holmes.

Sherlock turns his head away from his brother. "Stop," he pleads. Mycroft is confused, hurt, even. "Why?" he asks him softly. In the end, he nevertheless pick up the weapon and points it straight at his brother. He is a soldier today, and that is what soldiers do. His brother jokes about donating his brain and his small target of a heart. He jokes about the flowers at his funeral. All in his typical composed fashion. Sherlock can't help but grin at the banter, despite the gravity of the situation.

He wishes he can at least prolong this moment. The two brothers have finally reached a moment of understanding, where their animosity has been completely put aside. Mycroft has seen through Sherlock, knowing what choice he had made, and Sherlock has seen through Mycroft. They can smile together about ridiculous things like Mycroft's Lady Bracknell and the existence of a heart in a Holmes' brother.

John ruins the moment by protesting Sherlock's actions. Mycroft is forced to use the last weapon in his arsenal: taking the blame for the situation they find themselves in. It is truly horrifying, Sherlock thinks, that a man of Mycroft's intelligence and morality can commit such an error. It is even more horrifying to find out how little it took for two psychopaths to destroy lives. A five minute meeting behind glass barriers. "Five minutes!" Sherlock cries in anguish.

The cry echoes in his head, eerily reminiscent of a similar cry in a different life and death situation, but in reverse. Mycroft had been the one to shout it at his little brother. "Five more minutes and you would have been dead as a doornail!" Mycroft had been on his back about his drug use ever since he started at age sixteen. His "experiments" had started off small and with little damage, and then grown out of control as he began craving more stimulation. Mycroft had threatened, bribed, shouted, pleaded, and even had him arrested on occasion. His intervention had, if anything, made matters worse. Finally, Mycroft had told him that he was on his own. "If you want to destroy your own life, Sherlock, go right ahead. Mummy and Dad have no idea how to deal with you, and you have refused to cooperate with me. Do whatever you please, Sherlock, and see if anyone cares."

Sherlock had stormed out, and promptly proceeded to do just that. It must have been the first time in his life that he had actually listened to his brother without protest. Mycroft had felt guilty about his outburst, and began to search for him hours later. He found him in a dreadful drug den, in even more dreadful condition. The doctors at the hospital estimated that he would have survived no longer than five more minutes had help not arrived.

Even with top-level care, that Mycroft had arranged of course, it was touch-and-go for a while. Not knowing what Sherlock had ingested and injected made it difficult for the team to treat him. Mycroft had spoken to his brother before his discharge, in a tone of voice he had never used before. He was gravely serious, yet broken to the core. "I care about you, Sherlock, more than you will ever understand. I realize I can't control you. Nothing I do helps. So let's make a deal, brother mine. You do one small thing for me, and I leave you alone. Make a list. Make a list of whatever you take, and I'll be there if you need me."

Sherlock had of course inquired about Mycroft's intentions in the absence of a list. "Then I'll lock you up until you are clean. Prison, rehab, whatever will keep you safe. You may hate me for this Sherlock, but I will never let you destroy yourself like this. Not on my watch, Sherlock."

Thus started the years of ups and downs, where Sherlock would get clean and then relapse. When he felt he was in danger, he would sent a text to Mycroft, usually along the lines of "I hate you, you stupid prat. Where are you?" Mycroft knew to interpret it as an SOS signal, and would trace his phone and come rushing to the rescue. And read the list. While his brother convulsed and vomited, he would hold his head and whisper," Not on my watch, Sherlock. Not on my watch."

Sherlock looked at his brother, and was suddenly struck by a thought. When he had pictured imaginary Mycroft eating himself to death, he had known. The older brother was not suicidal, but had a fatalistic attitude. "All lives end. All hearts are broken. Caring is not an advantage." Who would talk like that? Someone who awaits, if not anticipates, death. Someone who spends his whole life trying not to care, because he believes death to be lurking just around the corner. Mycroft Holmes, a dead man walking.

"Not on my watch," he looks meaningfully at Mycroft, and points the gun at himself. He starts a countdown, hoping to but them all enough time for the chance to live again.