Christopher Columbus believes he can find an alternative route to the far East and persuades King Ferdinand and Queen Isabella of Spain to finance his expedition. But the Sultan of the Ottoman Empire, who makes a great deal of money through taxing the merchants who have to pass through his country on the Silk Road, sends his best spy, Fatima, to wreck the trip... When Robbie Coltrane declined the offer to play the title role, Jim Dale agreed to play Columbus to bring 'star power', out of affection and loyalty to the series and its producer and director.