 "Mark s Priory". the family seat of the Lebanons, is a house of terror to Ilsa Crane (Penelope Dudley Ward), secretary and niece of Lady Lebanon (Helen Haye). The strange behavior of two sinister butlers, Gilder (Roy Emerton) and Brooks (George Hayes), adds greatly to her fear and her sole consolation lies in the sympathy extended her by young Lord William "Willie" Lebanon (Marius Gording.) A young architect, Richard Ferraby (Patrick Barr), arrives from London to inspect the ancient home in regards to renovations, and he and Isla are immediately attracted to each other. Lady Lebanon tells her son that he must marry Isla to carry on the family name but Lord Willie tells her he has no intentions of marrying. Later, the family physician, Dr. Amersham (Felix Aylmer), arrives and it is evident he has some unrevealed hold over Lady Lebanon. The chauffeur, Studd (John Warwick), hints that he knew Aversham in India and that Aversham was discharged from the Indian Army under unsavory circumstances. Isla and Richard find the chauffeur murdered and the suspicion falls on the gamekeeper, Tilling (Torin Thatcher), whose wife (Elisabeth Scott) had been more than a little friendly with Studd. But Chief Inspector Tanner (George Merritt) and Deputy Sergeant Totty (Ronald Shiner) arrive from Scotland Yard and uncover evidence that points to Dr. Aversham as the killer, and Lord Willie substantiates the clue by telling them that Aversham had strangled a young Eurasian girl in India by using a red scarf and Studd, also, had been found strangled with a red scarf. The policeman are just about to fold up their tidy little case when a telegram arrives from "Mark s Priory" informing them that Aversham has just been found murdered---strangled with a red scarf. Well, back to the old drawing board.