Coldness settled over Mycroft as if Death had put his hand on his shoulder. Was that how it had always seemed to Sherlock, that he was always judging him for not being good enough? I can explain! But it was too late. For the first time, he knew Sherlock really meant it.
He slowly rose to his feet. His voice didn't sound real. "Better make that archenemy, Sherlock. Neither of us is ordinary enough to be each other's enemy."
He returned automatically to his office. He sat down in his chair and doubled over with his hands over his eyes.
Author's Note: This is the end of "Archenemy," but the story continues with "Not Your Housekeeper" (http:/www . fanfiction . net/s/6484644/1/Not_Your_Housekeeper), the tale of how Sherlock helps keep Mrs Hudson's husband on death row in Florida, with "Conscience (http:/www . fanfiction . net/s/6489370/1/Conscience), and with "Vulcan" (http:/www . fanfiction . net/s/6560821/1/Vulcan).
In case you're interested, here is how I see the timeline of Mycroft and Sherlock's lives from the beginning to the end of "Archenemy."
1969: Mycroft born
1976: Sherlock born
1983: Dad dies
1984: Mycroft tells Sherlock he's a sociopath
1985: Mycroft goes to Oxford
1992: Sherlock goes to Cambridge
1993: Mummy dies
1994: The Gloria Scott Affair
1995: Sherlock graduates from Cambridge
1995-1998: Lestrade gives Sherlock cases to work on
1998-1999: Work falls off
1999-2000: Sherlock goes back on cocaine, Mycroft gets him off it, they become enemies