Here's more of my "Love Story" fic. I decided to go angsty for this chapter because I couldn't let Holmes get away with his deception during the "Case of the Upside-Down Room." (That's one of the Deleted Sequences from the DVD.)
Also, I make references to the stories TWIS and YELL, even though they take place during Watson's marriage. The movie itself is very wonky on chronology, referring to cases like REDH and HOUN that should not have occurred yet, let alone been published. Not to mention that there was no Strand magazine in 1887, and there was no Russian ballet performance of Swan Lake in London before 1934. So to me this movie-verse is an alternate version of both the canon and real life history; here, there is no Mary Morstan, and she's either not mentioned in the cases, or Watson found some reason to make her up when fictionalizing the stories. So assume that Watson knows Isa Whitney only as a patient, not through Mary's friendship with Kate Whitney.