Born in 19th century Virginia into a large family, young Nancy Langhorne is shipped off to a New York finishing school.

Nancy meets and falls in love with Robert Gould Shaw, the debonair son of a Boston millionaire. They enjoy a whirlwind courtship in New York, but Nancy`s immaturity causes an unexpected problem.

Nancy and Robert Shaw now live on a large estate near Boston leading a grand social life, which Nancy finds increasingly shallow. With marital happiness eluding her, Nancy adopts a desperate course of action.

After their mother's death, Nancy and her sister are sent to Europe to socialise with the English high society. Here she attracts a bevy of suitors including Lord Revelstoke and Waldorf Astor, shy heir to a great fortune.

Nancy and Waldorf marry, move into their new home and after a year have their first child. Nancy encourages Waldorf to become a politician. Discontented with her own life, she discovers a kindred spirit in Philip Kerr.

Nancy discovers Christian Science and throws herself into war work. Waldorf's father - Viscount Astor - dies, leaving the title to Waldorf. Unable to seek re-election to the House of Commons, he decides Nancy should campaign in his place.

Nancy makes her maiden speech and is a success. She becomes a celebrity, but her private life is threatened by scandals involving her first husband, Robert Shaw, and their son, Bobbie.

Nancy has conflict with her children as they grow up, and as war looms she and Waldorf are publicly accused of harbouring the Cliveden Set.

Nancy fights for the people of Plymouth. As war ends, the mood of the country changes and Nancy loses popularity at Westminster. Waldorf tries to persuade her to resign.