Marlene Dietrich stars as the noble Domini Enfilden in this third film version of Robert Hichens' 1904 novel. After caring for her dying father, Domini is told by her Mother Superior (Lucille Watson) that she should go to the Algerian desert to rest and seek sanctuary. On her way to the town of Beni-Mora, Domini meets the ill-tempered and mysterious Boris Androvsky (Charles Boyer), a Trappist monk who has forsaken his vows and also seeks the Algerian desert for salvation. Domini is attracted to this moody monk, but continues on. Her desert guide, Batouch (Joseph Schildkraut), takes Domini to a cabaret, where a riot breaks out during a production number. Boris re-appears to rescue her from the trashed club. Domini and Boris fall in love, marry, and travel to the desert for their honeymoon. There the newlyweds encounter a unit of the French Foreign Legion, whose commander, De Trevignac (Alan Marshal), holds a secret to Boris's past.