Every woman will have her day.

London, England, on the eve of World War II. Guinevere Pettigrew, a strict governess who is unable to keep a job, is fired again. Lost in the hostile city, a series of fortunate circumstances lead her to meet Delysia LaFosse, a glamorous and dazzling American jazz singer whose life is a chaos ruled by indecision, a continuous battle between love and fame.