To cement a partnership between Protestants and Catholics in France, Margot de Valois (Isabelle Adjani) agrees to an arranged marriage to Henri of Navarre (Daniel Auteuil). Although she's a staunch supporter of Henri, she is not a loyal wife and takes up with a Protestant lover (Vincent Perez). During the St. Bartholomew's Night Massacre, she helps her lover escape, setting off a chain of events that alters their lives and the course of history.