Henry Daniell makes his 3rd appearance as Count Cagliostro, the evil alchemist. Lloyd Bochner is a professor who purchases a mirror from the count's castle. Professor Bochner starts see weird things in the mirror, which upsets his girlfriend, Marion Ross, before her "Happy Days."
Look for Frieda ("Return of the Vampire" fame starring Bela Lugosi) Inescort
as De Chantenay's Mother.