Villain(s)  Ape

Actor(s):  J. Carrol Naish, Shepperd Strudwick, Lynne Roberts, George Zucco

Brief Description  Dr. Renault's Secret is a 1942 American horror-mystery B-movie directed by Harry Lachman and produced by Twentieth Century Fox. Clocking in at a tight 58 minutes, it blends "mad scientist" and monster tropes typical of 1940s cinema. The film is particularly notable as the only surviving adaptation of Gaston Leroux's 1911 sci-fi novel Balaoo.

Plot:
The story takes place on the eve of Bastille Day in a remote, small French village. Dr. Larry Forbes arrives in town to visit his fiancée, Madelon, who lives at a secluded rural villa with her scientist father, Dr. Robert Renault. Upon arriving, Larry is introduced to Dr. Renault's bizarre, lumbering manservant and assistant, Noel. Larry notices that Noel exhibits distinctly ape-like tendencies and harbors a strange, protective attraction to Madelon.

As the night progresses, a string of mysterious, brutal murders plagues the village, coincides with Larry's arrival. While suspicion initially jumps between several eccentric locals—including a gruff ex-convict gardener named Rogell—Larry investigates the clues himself. He ultimately uncovers Dr. Renault’s dark, unorthodox secret: Noel is actually a wild ape that Dr. Renault successfully transformed into a human through disturbing, forced scientific experimentation. Despite the scientist's efforts, Noel's raw animal instincts cannot be suppressed, leading to a tragic and violent climax where the creation turns on the creator.

The movie is a loose remake of Fox's silent film The Wizard (1927), both based on Gaston Leroux’s Balaoo. Because Twentieth Century Fox rarely ventured into horror—a genre dominated at the time by Universal and RKO—this film has a unique visual flair, featuring high-quality cinematography by Virgil Miller and art direction by Academy Award winner Richard Day. For decades, Dr. Renault's Secret was considered a lost film until copies were rediscovered and restored in the early 2000s. It originally played in theaters as part of a classic horror double-bill alongside The Undying Monster (1942).