Concluding their regular weekly radio show, the cast of "Kay Kyser's Kollege of Musical Knowledge" head for Bellacrest Manor to perform at the 21st birthday party of pretty Janis Bellacrest (Helen Parrish). Arriving during a rainstorm, the radio performers are stranded when the drawbridge
is destroyed by lightning. The eerie mansion contains strange artifacts collected by its deceased owner, as well as Janis' silly aunt (Alma Kruger) and her guest, Prince Saliano (Bela Lugosi), a sinister medium. Also at the manor are retired judge Mainwaring (Boris Karloff) and the newly arrived
Professor Fenninger (Peter Lorre), a purported expert at debunking spiritualism, who h...