A Study in Pondlock: Origins

AU: "I am Amelia Pond. I am 24 years old. When I was a kid, I had an imaginary friend called 'The Doctor'.. But he.. Isn't real. The doctors, the real ones that is, say I invented him to cope with my parents' death. I suppose, after all these years, I've got to admit they've been right." Amelia Pond, mad, impossible, Amelia Pond. Sherlock's mad, impossible, Amelia Pond, but with Sherlock hidden under the cloak of his famed suicide, how could this even come to be?