 After Dr. Watson testifies at the inquest of the Honourable Ronald Adair, shot to death after returning home from his gambling club, he is followed back to his office by an eccentric bookseller who reveals himself to be Holmes in disguise. After the initial shock wears off, Holmes explains that he did not die in the fall that killed Professor Moriarity in their famous encounter at Reichenbach Falls in Switzerland three years earlier. Holmes has remained out of England to avoid Colonel Sebastian Moran, a Moriarity associate who witnessed Holmes  escape death and has vowed to kill Holmes in revenge. Holmes will try to foil Moran and solve the Adair murder.