This may be the worst of the Paul Naschy horror imports. The plot involves aliens reviving four monsters (the wolfman, a vampire, a mummy, and a Frankenstein monster - - although, they use the name "Farancksalan" in the movie) to conquer Earth. Sometimes, this movie uses the alternate title DRACULA VS. FRANKENSTEIN, even though the vampire is not Dracula (he's Count Meirhoff), there is no one named Frankenstein, although there is a Farancksalan Monster, and they never fight each other!
This was Michael Rennie's last movie before he died . . . a terrible way to end his career. Everything about it is bad, especially the make-up, which isn't even as good as some halloween costumes I've seen. This would have worked best as a kiddie matinee feature, but they would have had to cut out some stuff like a bloody open-heart surgery scene.