As jaded cabaret Madmoiselle Amy Jolly, (Dietrich) falls for Tom Brown (Cooper), a devil-may-care private in the French Foreign Legion. In spite on the clamor of other suitors, including man-of-the-world Kennington (Menjou), Amy arranges a rendezvous with Tom Brown when their aloof attraction turns to love. But when Tom overhears the wealthy Kennington propose to Amy, he accepts a dangerous assignment, convinced that only Kennington can give the beautiful chanteuse the life that she wants.
All proves fair in love and war, however, when on the eve of the engagement to Kennington, Amy steals away to find the man she truly loves.