Dr. Watson, who served in the English armed forces and was in the Afghan war, retires and returns to his homeland, in England. Since the financial situation of the doctor is very precarious, his long-time friend Mr. Stamford offers him to rent a room in the house at 221-B Baker Street, which is rented by an elderly lady - Mrs. Hudson. The second rented room is already occupied by another gentleman - the mysterious Mr. Sherlock Holmes. Holmes makes an ambiguous impression on Watson. He conducts complex chemical experiments with blood, plays the violin, has the deepest knowledge about cigar ash, London dirt and criminal law, but at the same time demonstrates complete ignorance of well-known truths (for example, the fact that the Earth revolves around the Sun), does not read fiction, as well as books on history and philosophy. At the same time, very strange visitors constantly come to Holmes, and on the table he has portraits of personalities of a disgusting appearance.

Holmes receives a message from Inspector Gregson (Igor Dmitriev) about a strange case in an abandoned house on Brixton Road: the body of an elderly American was found there, and the word "Revenge" is written in blood on the wall.

Mycroft Holmes hands Sherlock Holmes the case of the Master Blackmailer.

After upsetting the criminal underground in 'the Master Blackmailer' case, Sherlock Holmes has to face his archenemy: Prof. Moriarty.

Dr. Watson executes Sherlock Holmes' will, who faced death after exposing Moriarty and his gang in the previous episode.

When Sir Charles Baskerville is found dead in his country house, Dr James Mortimer asks Sherlock Holmes for help to save Sir Henry Baskerville, the only known heir, from the curse that haunts Baskerville family.

Holmes and Dr. Watson help a young lady who is receiving anonymous letters 10 years after her father passed away under shady circumstances. They find themselves in an enigma involving a treasure, murder and a love interest for Watson.

This film version was released before the premiere of the full two-part television version (The Adventures of Sherlock Holmes and Dr. Watson: The Twentieth Century Approaches). In this version the entire plot of the story “Bruce-Partington Drawings” was deleted.