Adapted from "The Final Problem" and "The Adventure of The Empty House"
by Sir Arthur Conan Doyle

This new, full-length play pits Sherlock Holmes against his greatest opponent -- the criminal mastermind, Professor Moriarty, in a dangerous game of cat-and-mouse that ends in a climactic death struggle between the two men above the Reichenbach Falls in Switzerland. Three years later, Dr. Watson, bereft of Holmes and lacking his late friend's superior detection skills, is nonetheless recruited by Scotland Yard to assist with an investigation into the murder of a young, London aristocrat -- the Honorable Ronald Adair, who has been discovered fatally shot in the locked bedroom of his 427 Park Lane address. With no apparent motive for the killing and lingering questions about the murder weapon, Watson and the police are left baffled by the 'Park Lane Mystery,' until, just outside the crime scene, the good doctor bumps into a wizened, old book collector, who follows him home and unexpectedly sheds some valuable light on the case.