Norwegian resistance fighter Erik Bergman (George Chakiris) offers the British Royal Air Force an irresistible target when he reveals the location of a secret Nazi factory. American pilot Roy Grant (Cliff Robertson) commands the fighter squadron ordered to take out the plant, but he discovers that the location is even more formidable than he had been told. When the promised ground support troops fail to show up, Grant fears he and his men are on a doomed mission.