When M. Beaucaire, a handsome barber, catches the Duke of Winterset cheating at gambling, Beaucaire exacts Winterset's cooperation in sneaking Beaucaire into a great ball, disguised as the Duke de Chartres, and to introduce him to the beautiful Lady Mary. The disguised barber successfully pulls off the masquerade and is soon the toast of society. But Winterset is embittered at having been blackmailed so, and he sets out to destroy Beaucaire if he can do so without revealing his own duplicity.