The disaffected wife of a failed civil servant, is thrilled to re-encounter Octavio, a former lover who is now a union activist on the run from a corrupt politician. Hoping to help him, she descends into the Mexican underworld, where she finds a purpose-and a thrill-missing from her married life.

Colonel John Wister, on duty with the British army in the desert region of Dubik, returns to England on leave. There he falls in love with Julia Ashton, who cares deeply for him but believes herself incapable of love following the death of her fiancé; some time before. Wister convinces her that he loves her enough to live without her romantic love and that she should marry him. She does so and returns to Dubik with him. There she meets his adjutant, Captain Denny Roark. Roark is a dashing young man who reminds Julia thoroughly of her lost love. Soon she finds she is indeed capable of love, but it is Roark with whom she falls in love, not her husband. As warfare with the local tribes heats up and as Wister gains awareness of the unconsummated romance growing between his wife and best friend, tragedy lurks.