During World War II, a British aircraft is shot down and crashes in Nazi held territory. The Germans capture the only survivor, American Brigadier General George Carnaby (Robert Beatty), and take him to the nearest S.S. headquarters. Unknown to the Germans, the General has full knowledge of the D-Day operation. The British decide that the General must not be allowed to divulge any details of the Normandy landing at all costs, and order Major Jonathan Smith (Richard Burton) to lead a crack commando team to rescue him. Amongst the team is an American Ranger, Lieutenant Morris Schaffer (Clint Eastwood), who is puzzled by his inclusion in an all British operation. When one of the team dies after the parachute drop, Schaffer suspects that Smith's mission has a much more secret objective.