Lucille is a teacher at a girls' school in nineteenth-century England, but her twin sister, Susanna, is a high-class courtesan. One day, Susanna shows up at Lucille's door, asking Lucille to pretend to be her and stay at their late father's house while Susanna is away! Lucille can't say no to her sister, so she agrees to play the part of a courtesan, but what will she say when her new landlord, Count Seagrave, asks her to become his lover?