Col. Cal Rhodes, a retired U.S. army colonel and father of a Vietnam War casualty organizes a special private fighting force, ten years after his son is reported missing to help him infiltrate Vietnam in search of his son and other Americans held captive. Refusing to believe that his son is dead, Rhodes contacts an old friend, oil baron MacGregor whose son is also missing, and recruits some his son's marine pals and other tough ex-servicemen. Rhodes personally drills them on a specially prepared private training base.
In Asia, their mission faces several setbacks. US government officials, who claim they are negociating with the Vietnamese, think that he will hamper their efforts and try to stop them. The CIA informs the Bangkok police who confiscate Rhodes` small arsenal. Eventually he and his men reach their target. In a bloody battle with a horde of prison guards, they manage to rescue the captives. Rhodes learns that his son has died earlier, but nonetheless considers the mission a success.