Nightmare castle

A deranged scientist, Dr. Stephen Arrowsmith (Paul Muller), catches his beautiful wife, Muriel (Barbara Steele), conducting an affair with their gardener, David (Rik Battaglia). The enraged Arrowsmith imprisons the lovers in his laboratory. Chained to the wall, Muriel and David suffer slow, painful deaths as the vicious Arrowsmith inflicts sadistic torture upon them. Believing he has achieved his vengeance, the doctor isn't pleased when his victims return from the grave to seek theirs.