Gladys Mitchell wrote some 66 mysteries starring the witty and clever Mrs. Adela Bradley (Rigg). A wealthy divorcee, Mrs. Bradley has a knack for investigations and a helpful chauffeur, George Moody (Dudgeon). In 1929, Adela is invited to the country estate of friends to celebrate Eleanor Bing's (Fielding) engagement. Only her fiance is murdered and then doesn't turn out to be what he seemed. But then, neither does anyone else.