Real-life lovers Vivien Leigh and Laurence Olivier star in this Regency-era romance. After an ageing and dishevelled Lady Hamilton (Leigh) is thrown into prison for disturbing the peace, she begins to recount the dramatic story of her life to her cellmates, including her rise to notoriety as the mistress of the great Lord Nelson (Laurence Olivier) while still unhappily married to the much older British Ambassador Sir William Hamilton (Alan Mowbray).