Keira Knightley and Ralph Fiennes star in this historical drama set in late 18th-century England. Georgiana Spencer (Knightley) was in her teens when her mother (Charlotte Rampling) arranged her marriage to the Duke of Devonshire (Fiennes). As the Duchess, she endures a marriage that's loveless and rampant with infidelity on the part of her husband. After becoming inured to his lifestyle, Georgiana even raises the Duke's illegitimate daughter as her own. Meanwhile she takes an interest in local politics, working for Whig causes to become a darling of the common people. During her time the Duchess was also regarded as a fashion icon and a doting mother. Unfortunately, a passionate affair with Earl Grey (Dominic Cooper), the future Prime Minister, proves to be her undoing.