Isabelle Adjani stars as Margaret of Valois better known as Margot daughter of scheming Catholic power player Catherine de` Medici. Although Margot herself is excluded from the throne by the Salic Law her marriage to a Protestant prince offers a chance for domestic reconciliation during the late 16th century reign of the neurotic hypochondriac King Charles IX a time when Catholics are vying for political control of France with the French Protestants the Huguenots. Catherine decides to make an overture of goodwill by offering up Margot in marriage to prominent Huguenot and King of Navarre Henri de Bourbon although she also schemes to bring about the notorious St. Bartholomew`s Day Massacre of 1572 when thousands of Protestants are slaughtered. The marriage goes forward but Margot who does not love Henri begins a passionate affair with the soldier La Mole also a Protestant from a well-to-do family. Murders by poisoning follow as court intrigues multiply and Queen Catherine`s vi