Grace Milroy loses her job working at a factory. However, through a strange set of circumstances, she is taken on as housekeeper at the nearby Swinford Castle the home of the eccentric Duchess of Swinford.
In London a young lady meets a homeless and apparently penniless Russian prince. She introduces him to her middle-class Fulham family and he moves in. It turns out he still has a number of diamonds given him by the last czar, and he is persuaded to start selling them. The resulting money, and his princely notoriety, soon cause changes in everyone's lives.