Mrs. Bradley, with her trusty chauffeur George, arrives at Chayning Court for the engagement party of her god-daughter, Eleanor Bing. Later that evening, Eleanor's fiance is found dead in the bath. The police are called in and conclude that his death was nothing more than a tragic accident, but Mrs. Bradley is not satisfied. She launches her own investigation, using her prodigious charm and wit to help the local police catch a killer.