A crack team of Allied soldiers stages a daring rescue during World War II. A U.S. general is being held captive in an imposing castle fort, high in the Bavarian Alps. The audacious plan calls for Lt. Schaffer (Clint Eastwood), Maj. Smith (Richard Burton) and other operatives to parachute down wearing Nazi disguises. They'll penetrate the mountain outpost while undercover operatives assist them from within. But their mission changes when they discover that there's a traitor in their midst.