A young flapper tricks her childhood sweetheart into marrying her. He really loves another woman, but didn't marry her for fear the marriage would end in divorce, like his parents'. Complications ensue.

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.