THE SIGN OF FOUR (B2.1)

Sherlock Holmes is bored. But a fascinating new case is just around the corner. The attractive Mary Morstan arrives at 221B Baker Street with a strange story to tell. Her father vanished ten years ago: four years later she receives six beautiful pearls, one each year. She has been invited to meet the sender of these pearls and asks Sherlock Holmes and Doctor Watson for their help.