A jeweller is killed in a gang robbery leaving the daughter as the only witness. When the police can't build a case against him she decides to go undercover to infiltrate the home of the killer's brother. Slowly she is drawn into the world of the rival gangs.

On New Years Eve, 1899, baronet's son Edward Courtney becomes engaged to Kate, his mother's maid, much to the scandal of London society. The film then follows their family through four generations, with separations, joys, tragedies, and service in the Boer War, WWI, and WWII.