A partly fictionalized account of history begins with the arrival of slatternly Emma Hart, a cook's daughter, at the home of Charles Greville. Greville takes her as his lover and grooms her until their relationship becomes an inconvenience. Greville then dupes Emma into traveling to Naples to live with his uncle, Lord Hamilton, ambassador to the court at Naples. Realizing that Greville has abandoned her, Emma agrees to marry Lord Hamilton. Soon, however, she meets Admiral Horatio Nelson of the British Navy. Emma plays a crucial role in convincing Naples to open its ports to Nelson during his campaign against Napoleon's French fleet. Soon, Emma and the married Nelson become romantically involved -- a relationship which will have consequences for them both.