Kate Croy's (Helena Bonham Carter's) mother was born to wealth and privilege, but she threw it all away to marry Kate's Father (Sir Michael Gambon), a penniless opium addict who admits to having stolen from his wife. After her mother's death, Kate is offered an opportunity to return to the life her mother gave up. There is one condition, however: Kate must sever all of her old ties, not only to her father, but also to her lover, the muck-raking journalist Merton Densher (Linus Roache), whom she has promised marriage. Kate reluctantly agrees to this, and in the meantime becomes friendly with "the world's richest orphan", Milly Theale (Alison Theale), an American making the Grand Tour. Desperate to see Kate, Merton crashes a party that she and Milly are attending, and Milly is attracted to him. When Kate learns that Milly is dying, she comes up with a plan to have her cake and eat it too, but all does not go as planned.