It has been alleged that Horror Island was the least expensive of Universal's 1940s horror films. While it certainly looks that way, it remains an enjoyable outing from fade-in to fade-out. In the tradition of "Ten Little Indians", a group of disparate types are lured to a supposedly haunted mansion on a remote island. Their "host" is peg-legged privateer Tobias (Leo Carrillo), who possesses half of a valuable treasure map. One by one, the treasure-hunters are killed off by a mysterious assailant, with Tobias the first victim. The identity of the "mystery" killer is fairly obvious from the outset, though the screenplay cheats a bit by rendering the villain helpless during one of the murders. Of the stellar all-character-actor cast, Iris Adrian shines as a leather-lunged blonde, alternating between wisecracks and shivers throughout the film's brisk 61 minutes.