Eccentric consulting detective Sherlock Holmes and Doctor John Watson battle to bring down a new nemesis and unravel a deadly plot that could destroy England.
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.
When Dr. Watson tries to apply Sherlock Holmes' method, he quickly discovers that it is harder than it looks.
Holmes and Watson board a passenger train bound from London to Edinburgh, to guard the Star of Rhodesia, an enormous diamond worth a fortune belonging to an elderly woman of wealth; but within the first hour of the trip, the woman's son is murdered and the diamond stolen and any of the passengers in their car could be the killer thief.
A convicted thief in Dartmoor prison hides the location of the stolen Bank of England printing plates inside three music boxes. When the innocent purchasers of the boxes start to be murdered, Holmes and Watson investigate.
In the midst of World War II, Sherlock Holmes rescues the Swiss inventor of a new bomb-sight from the Gestapo and brings him to England, where he quickly falls into the clutches of the evil Professor Moriarty.
Sherlock Holmes and Dr. Watson meet as boys in an English Boarding school. Holmes is known for his deductive ability even as a youth, amazing his classmates with his abilities. When they discover a plot to murder a series of British business men by an Egyptian cult, they move to stop it.
When a nobleman is threatened by a family curse on his newly inherited estate, detective Sherlock Holmes is hired to investigate.
Sherlock Holmes and Dr. Watson look into reports that a huge, vicious hound has killed Lord Charles Baskerville and that Lord Henry Baskerville is the next to be killed.
Holmes and Dr. Watson take on the case of a beautiful woman whose husband has vanished. The investigation proves strange indeed, involving six missing midgets, villainous monks, a Scottish castle, the Loch Ness monster, and covert naval experiments.
Colonel Barclay is found dead and his wife is arrested for the murder, but Holmes is convinced a missing door key will reveal the true killer.
Holmes receives a mysterious telegram from Cyril Overton, the captain of the Cambridge University rugby team. Overton later explains that one of the best players on his team, a young man named Godfrey Staunton, went missing while in London for an important game. Holmes follows a trail of clues back to Cambridge.
A governess is arrested for the murder of her employer's wife.
A gentleman is baffled when the childish drawings of little dancing men terrify his American wife. Sherlock Holmes soon discovers why.
Susan Cushing asks Holmes' help in solving the disappearance of her sister Mary Browner, but it doesn't seem Holmes' type of case until he is told of a Christmas present's grisly contents.
Hilton Soames, a lecturer in Greek at a university, notices that someone has gone into his study and looked at the text for an unseen translation exam that is due to take place the next day. Suspicion falls on the three students who live in the same building in which Soames lives and works, all of whom are entered for the exam.
A German spy named Von Bork has been in England since 1910. Through several agents, he has gathered a significant amount of information relating to the British armed forces and foreign policy. He is unaware that a large amount of that information is false because one of his agents is really Sherlock Holmes, who is working for the British government.
Dr. John Watson treats a patient who has lost a thumb. The patient says that the loss of his thumb was not an accident but the result of an attack. However, he fears that the story behind the loss of his digit is so strange that the police will not believe it.
Sherlock Holmes investigates a series of so-called "pajama suicides". He knows the female villain behind them is as cunning as Moriarty and as venomous as a spider. Based on "The Sign of Four" and the short stories "The Dying Detective", "The Final Problem", "The Speckled Band" and "The Adventure of the Devil's Foot".
A young woman turns to Holmes for protection when she's menaced by an escaped killer seeking missing treasure. However, when the woman is kidnapped, Holmes and Watson must penetrate the city's criminal underworld to find her.