The Progress of Sherlock Holmes by ivyblossom
Sherlock, Sherlock/John, John/Mary.
This is it: the fic to end all fics. For me, at least. Absolutely epic first person Sherlock stream-of-consciousness story (the near-elimination of "I" is a masterful, masterful stylistic choice) that is one long, painful, gorgeous deduction on the science of life and love and bonds and betrayal and trust and hope and lordy, what a paradox. Pinged every infidelity squick I have, but for everyone involved, which made it fascinating. And, in the grand scheme of things, it's probably the hurtiest thing I've ever read, ever, but in the most amazing way possible. I laughed and cried and stopped to clutch feebly at my chest every few chapters (and lines, and words). I legitimately forgot it was fanfiction, and I can't wait to read the whole thing again. Perfection. Perfection.