Cast & Crew
In rural England at the turn of the century, Oliver Hammond and his sister Helga are the last of the aristocratic Hammond line, which has been plagued for centuries by a family curse. According to village legend, the curse began when a distant Hammond ancestor sold his soul to the devil, and for centuries since has resided in a secret room in the mansion, from which he periodically emerges in the shape of a monster to sacrifice another human being to prolong his own life. One night, Helga becomes anxious when Oliver is late returning home from the laboratory of their friend, Dr. Geoffrey Covert. Her fears are realized when she hears the screams of Geoff's nurse, Kate O'Malley, and discovers that both Kate and Oliver have been attacked by a mysterious creature. Although Oliver is not mortally injured, Kate sinks into a coma, and Geoff is not optimistic about her recovery. The next day, Helga consults Scotland Yard Inspector Craig, and he summons Bob Curtis, the chief of their laboratory staff, and Bob's assistant, Cornelia "Christy" Christopher. Christy, who loves supernatural phenomena, is thrilled by the chance to investigate the "Hammond monster," but Bob has a more skeptical view about the nature of Oliver and Kate's attacker. Helga reluctantly allows Bob and Christy to accompany her to Hammond Hall, where Bob is intrigued by Geoff's attempts to interfere with the investigation. Bob receives little help from the servants, Walton, Mrs. Walton and Stredwick, although Mrs. Walton does confide in him that Kate appears to be drugged. After Kate dies, an inquest is held, with the verdict stating that she was attacked by persons or species unknown. Bob vows to prove that her death was murder and returns with Christy to London, where he performs forensic tests using spectrum analysis. Bob determines that wolf hair was present at the scene of the crime, and that a scrap of a scarf found there came from Oliver's scarf, which Walton had attempted to burn after the attack. Bob then goes back to Hammond Hall, and after obtaining a blood sample from Kate's body, uses Geoff's laboratory to establish that she was drugged with cobra venom. Although he admits that he knows the full truth behind the case, Geoff refuses to tell Bob, but their discussion is interrupted by an ominous howl coming from the direction of the hall. Bob and Geoff are then joined by the police as they chase the myserious monster, who has abducted Helga, through the moors. The monster is shot, and as it dies, it transforms into Oliver. Later, Geoff explains to Bob and Christy that for many generations, Hammond men have suffered from lycanthropy, and that Geoff was secretly using cobra venom to treat Oliver, who was unaware of his condition. When Oliver transformed into the monster and attacked Kate, she was infected by the venom, and Walton, who knew the truth, had tried to burn Oliver's scarf to protect him. Geoff assures them that Helga will recover, and Bob and Christy leave for London.
Harry M. Leonard
Walter M. Scott
According to contemporary sources, George Sanders was originally cast in this film and was suspended by Twentieth Century-Fox when he refused to accept the role. According to studio publicity, Sanders was to have played the part of "Bob Curtis," but in an interview with the New York Times, he stated that he turned down the film after being ordered by the studio "to report for work...dressed as a gorilla." A September 17, 1942 Hollywood Reporter news item noted that Fred Sersen was taking a camera crew to Del Monte, CA to obtain "sea shots." Hollywood Reporter news items and the Hollywood Reporter review reported that Twentieth Century-Fox intended for The Undying Monster to be exhibited on a double bill with Dr. Renault's Secret, another horror picture released by the studio in 1942.