Steve McQueen stars as a navy lieutenant with a foolproof scheme to get rich by winning at a Venice casino with the help of The Honeymoon Machine. While playing poker with his pals, Lieutenant Fergie Howard (McQueen) gets the news that Operation Honeymoon has been successful: His ship's onboard computer can predict exactly where a missile will land. A great advance for world peace--and a great idea for how to make a million! The ship's computer tech (Jim Hutton) confesses that the computer can also tell where a roulette ball will land. As soon at their ship docks in Venice, Howard secretly wires the computer to a high-class casino, and the money starts to roll in. But when the admiral sees signals coming into the computer, he assumes that real missiles have been launched!