This action-adventure film is based on a novel by Edgar Wallace. In the story, Colonel Smith (Ernest Borgnine) is an aging military man whose son is a CIA agent. His son has been captured by a bevy of iron-curtain bad-guys involved in a civil war in the African country of Angola, and Col. Smith is determined to rescue him. He puts together a group of military types to effect the rescue, and runs afoul of all sorts of nefarious characters in the process, including an East German military advisor (Robert Vaughn) and a shady diamond company security chief (Oliver Reed). Lovely Sam (Nancy Mulford) adds visual interest to the rescue team, and manages some dandy hand-to-hand combat moves.