 In the battle front of espionage and code cracking of World War II, there remains but one task on the Allied agenda: the capture of a German "Enigma" machine which will allow the Allied naval forces to locate and track submerged German U-Boat submarines. When one such German vessel breaks down after a battle with British forces, a secret mission is dispatched to take over the U-Boat by commando American forces and retrieve an Enigma machine intact. The raid goes well, at first, yet following the destruction of the American mothership and the arrival of reenforcement German ships, the Americans trapped on the U-Boat must use their training and wits to pilot U-571 in order to save their lives.