The film follows the story of Mary Boleyn (Natascha McElhone), sister to Anne Boleyn and George Boleyn, 2nd Viscount Rochford. Henry VIII of England (Jared Harris) favours Mary, recently married to William Carey (courtier), and lady-in-waiting to his wife, Catherine of Aragon. Despite her objections, Mary is forced by her ambitious family to become the King's mistress. Although Mary at first despairs that her husband has consented to the arrangement, and feels guilty whenever she serves the Queen, she begins to come to terms with her fate.