When 1 of 2 Foreign Legion officers is killed after witnessing a secret experiment on a death ray (capable of shooting down aircraft) in southern Morocco, the other gets vengeance by infiltrating the organization responsible.

In Lebanon, industrialist Hennequin, director of a French oil company, entrusts engineers Jean Domèvre, a Frenchman, and Mokhrir, a Lebanese, with the prospecting of an isolated region granted to him by Countess Athelstane Orloff. Their search remains fruitless until Mokhir reports the discovery of a uranium deposit, but disappears before Jean can identify the location. He goes to the Countess for help in finding Mokhir and surprises her when, due to financial difficulties, she is negotiating her concession with the Englishman Hobson, director of a rival company. Attracted by Jean, the Countess nevertheless gives him her preference and they set off together in search of Mokhir.

During a walk along the cliffs not far from Marseille, Elisa Langerot sees her husband slip and fall to his death. Inexplicably, Elisa flees the scene of the accident, stops a passing driver and tells him a made-up story about a stolen car, concealing her husband's death. Feeling sorry for the girl, the driver, Philippe Morçot, gives her a lift and later lets her stay at his house. The good deed, however, doesn't go unpunished, and soon Philippe is drawn into Elisa's twilight world of fantasies, lies and paranoia.

1959 film by Jean Delannoy

In this romance, a jilted lawyer joins the French Foreign Legion to help him forget his faithless love. While in the desert he espies a village beauty who is the exact double of his true-love.