In exchange for helping writer-adventurer Lawrence Colby smuggle 300 watch parts into Paris from Switzerland, Martine Randall asks Colby to help solve a complicated situation involving her friend Sabine Manning, a well-known author of sex novels.

Brothers Beau, John and Digby Geste join the Foreign Legion, where they fall under the rule of tyrannical Sergeant Markoff. Beau and John are assigned to Fort Zinderneuf, where Markoff tries to break their spirit, aware of a dark family secret concerning a fabulous jewel one of them carries. As tensions rise, Arabs attack the fort and rivalries must be thrown aside in a desperate battle for life.

When an experimental flying saucer crashes, secret agent Matt Helm has to bring back the secret weapons hidden on board.