The year is 1888 & Miss Mary Morstan finds herself at the centre of a mystery seemingly too complicated to unravel Following the disappearance of her father she is sent each year an anonymous gift of a beautiful pearl When she receives a mysterious message to meet her unknown benefactor she seeks out the help of Sherlock Holmes & Dr Watson & there follows an exotic tale of treasure intrigue betrayal & murder The great detective leads his companions on a wild chase for answers as they hunt down a killer & try to unravel the truth behind the Sign of Four