Lee Marvin is Sergeant Ryker, an American Marine during the Korean War who supposedly defected to the enemy in the North. He had already been sentenced to death by hanging for this crime, but his defense attorney doesn't believe there's been a fair trial. Ryker claims he was sent on a mission by his C in C who has since been killed in action and there is no evidence that Ryker is telling the truth. Under intensive and persistent investigation the defence attorney uncovers new evidence which could possibly eliminate any sense of guilt against Ryker, however the officers on the bench are convinced he's guilty and do everything to hinder the defences investigation.
