An old-fashioned spy thriller in the vein of 1940s espionage movies and based on an international best-selling novel, Enigma stars Dougray Scott as Tom Jericho, a young mathematics expert who was a central force in the decoding of a Nazi network and has just been released from a sanitarium for an apparent nervous breakdown. He is put back to work in Britain in 1943, where he is called upon to regear their computer system and determine a new German code. If he fails to discover the information, the war's largest convoy of Allied ships heading to Great Britain from the U.S. will be targets for massing Nazi U-boats. Jericho learns of a possible traitor who has tipped off the Germans of the code-cracking, and who may be in the form of Claire (Saffron Burrows), a sexy blonde who has disappeared and who was once his girlfriend. Jericho must now, with the aid of an intuitive clerk (Kate Winslet), calm his infatuation with Claire, who may be his undoing, as well as single-handedly finish his assigned task, which has been said to take an entire team about one year's time.