Sergeant Brock (Gene Barry) and Goldie (Nat King Cole) are American Korean War veterans now serving as French Foreign Legion mercenaries in the First Indochina War. Angie Dickinson plays Brock's wife, a "half caste" Chinese Eurasian named "Lucky Legs" who resorts to smuggling to feed her five-year-old son she had with Brock. Brock abandoned her and the child when it was born with Asian features, feeling a "half breed" would not be welcome in America; an attitude towards miscegenation prevalent (in some quarters) at the time. Lucky is recruited by the French high command to use her knowledge to guide a demolition squad of Legionnaires led by Brock to blow up a hidden Viet Minh ammunition dump on the border with Red China. In return for her services, Lucky is promised by the French that they will arrange for her son's evacuation to America.