Pre-war intelligence man Tommy Blythe interrupts his honeymoon to investigate the discovery of vital Air Ministry blueprints on a woman killed in a London road accident. The trail leads to a boarding house in Notting Hill and its varied tenants.
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.