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.
A young heiress finds evidence suggesting that at night she acts under the influence of a family curse and has begun committing ghastly murders in a nearby park.
London, 1761. St. Mary's of Bethlehem, a sinister madhouse, is visited by wealthy people who enjoy watching the patients confined there as if they were caged animals. Nell Bowen, one of the visitors, is horrified by the deplorable living conditions of the unfortunate inhabitants of this godforsaken place, better known as Bedlam.
An unsuccessful sculptor saves a madman named "The Creeper" from drowning. Seeing an opportunity for revenge, he tricks the psycho into murdering his critics.
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.
An architect, visiting an English country house, realizes the other guests are familiar from his recurring nightmare. When they share their tales of the supernatural, he is filled with a growing dread.
On a Greek island during the 1912 war, several people are trapped by quarantine for the plague. If that isn't enough worry, one of the people—a superstitious old peasant—suspects a young woman of being a vampiric demon.
Sherlock Holmes investigates when young women around London turn up murdered, each with a finger severed. Scotland Yard suspects a madman, but Holmes believes the killings to be part of a diabolical plot.
In 1903, Doctor Huntington Bailey meets a friendly older lady during a train trip. She tells him that she is going to visit her brother Nick and his lovely young wife Allida. Once in New York, Bailey hears that his train companion suddenly died. Shortly afterward, he meets the strange couple and gets suspicious of Nick's treatment of his wife.
The famous Borgia Pearl, a valuable gem with a history of bringing murder and misfortune to its owner since the days of the Borgias, is brought to London, thanks in part to Sherlock Holmes. But before long the jewel is stolen, due to an error on Holmes' part, and shortly thereafter, a series of horrible murders begin, the murderer leaving his victims with their spines snapped and surrounded by a mass of smashed china.