It's a good thing that Mycroft Holmes is capable of the impossible, because his brother consistently demands it.
Time and time again, Sherlock has managed to get himself into the worst kinds of trouble. Charges of theft, of murder, kidnapping, possession… The list goes on and on, and each expunction should have been more difficult than the last. They were, but Mycroft never told that to his brother. There wasn't any point.
It certainly helps train his staff. The chaos that trails along in Sherlock's wake is not to be underestimated, and his people grow sharp on it.
So when Mycroft receives the report that Sherlock's smoking and drinking and cocaine use have caught up with him, that his heart is failing, his team is already scouring the world for a donor. It takes longer than Mycroft would have liked and far less time than anyone acquainted with the field of organ transplants would have believed, but they find one.
John Watson, military doctor. Sent back from Afghanistan with a wounded shoulder only to be killed in a traffic accident once back on London's soil. It's tragic, Mycroft supposes, but that doesn't matter. His blood checks out, and his brother's going to live.
The transplant goes well. Sherlock would be out of the hospital in record time, but first there's the business of making sure that there will not be a repeat of this incident, and this time Mycroft is damn well going to put his foot down and make sure Sherlock knows the consequences of his actions.
Sherlock listens and nods and glares balefully, calculates his chances of survival in his mind and wishes, on some level, that Mycroft had just let him die. It would have been easier.
He acts a little differently after that, and people accept it because they know what happened. So what if he's taken to fuzzy jumpers and excessive amounts of tea and limps somewhat? His mind is as sharp as ever, or so they think.
Until, that is, he shows signs of being aware of other people as if he doesn't think of them as specimens. Until he starts flirting with young women, flirting well, apologizing for his rough behavior and lack of consideration. Sherlock Holmes becomes human after the transplant, and that is a shock.
He has screaming nightmares of a place he doesn't recognize, a war he never fought, a battlefield that has never been his own, and then he wakes up and he's in London and he's terrified because every moment that ticks by he's a moment closer to his death and it's looming painfully real, and Please God, let me live.
He's inspecting the body of a woman dressed in pink, the latest of a spate of suicides, when he cracks.
He calls his deductions as he makes them, words bullets that ricochet around the room, most finding their intended recipient with Lestrade's evidence bags and a few braining Anderson. This is a novelty, for the man who spends so much of his time inside his own head. And then, recoil, when he's finished, the word pops into his mind.
Amazing.
It's not his own thought, can't possibly be his own thought, and he knows in that instant that this has just gone far too far and he is on borrowed goddamn time and he is going to die.
So when he's talking to the cabbie, knowing that he's going to end it now, tonight, finally, he tells him the truth. Tells him the prognosis, the ever-marching numbers that terrify him so.
"Death," he says darkly, "Will be a relief."
Mycroft Holmes is capable of the impossible, has done it. Has gone to Hell and back for the sake of his brother.
This time, he doesn't even make the attempt.
A/N: Done for a prompt on the Kinkmeme in which heart transplant. This is not only an AU in that it diverges from canon, but also in that it diverges from reality. Heart transplants do not work this way.
~Mademise Morte, November 20, 2012.