 Naschy claimed he followed up this film with his 1968 film "Las Noches del Hombre Lobo" (which is today a lost film, if indeed it was ever made at all, since no one has ever seen it) and his 1969 film "Los Monstruos del Terror".A drunken Gypsy couple spending the night in the abandoned Castle Wolfstein accidentally resurrect the werewolf Imre Wolfstein when they remove the silver cross from his corpse.Once alive, he not only kills the Gypsy couple, but also wreaks havoc on a nearby village.