An eclectic group of characters set sail on Captain Lansen’s leaky cargo ship in an attempt to escape their various troubles. When a violent storm strikes, the ship is swept into the Sargasso Sea and the passengers find themselves trapped on an island populated by man-eating seaweed, giant crabs and Spanish conquistadors who believe it’s still the 16th century.
A notice in a newspaper seeks red-headed men, inviting them to join a league which will pay them well - and Jabez Wilson, a pawnbroker who responds, finds he is hired and paid generously for spending four hours a day copying an encyclopedia in long hand. When the league is suddenly dissolved, Holmes is asked to find out what has been going on, and he quickly suspects crime. Indeed, behind this curious arrangement lurks Holmes's arch-enemy, Professor Moriarty.
The French government sends for Holmes when the Mona Lisa is stolen from the Louvre. Holmes swiftly decides he is dealing with a mastermind - and none other than his old enemy Professor Moriarty himself.Holmes foils Moriarty's plans to sell Leonardo da Vinci's masterpiece and trails him to Switzerland, where they meet and fight to the death above the famous waterfall at Reichenbach.
Three years on from Holmes's fatal fall into the Reichenbach Falls, Watson wrestles with a murder case under his own steam. But who is the enigmatic stranger in the Coroner's court, listening intently to all the evidence? Holmes returns home and explains how he escaped death at Reichenbach, while Moriarty lost his life. Holmes and Watson must now bring a partner of Moriarty's to justice, by proving he is a murderer.