The Gist: Dr. Frankenstein moves into Dracula's castle and resurrects his dead body in order to use the vampire to do his bidding.
Clarification: I don't know much about the background of the making of this movie but by watching it it's very obvious that this film as well as Dracula's Daughter was made at the same time as they have pretty much the same cast and same setting though this film would be a lot tamer than Dracula's Daughter which was released two months after this one.
It's not a very strong film story wise and can be summed up pretty effortlessly. Basically Dr, Frankenstein resurrects Dracula, Dracula attacks a few people, The Dr. regrets resurrecting Dracula and destroys him, the end. Unlike many of Jess Franco's films this one can't be described what so ever as erotic horror though. There is no nudity or eroticism whatsoever in this one. Obviously if you saw my review for Dracula's Daughter he more then made up for it with that one.
Selling Point: Another opportunity to see Britt Nichols with fangs.
Female Vampire Factor: As mentioned above it's pretty much the same cast as Dracula's Daughter so this would be the first of two films were Nichols would be playing a sexy vampiress but this film is not even in the same league as the other one in the "Sexy" category. Here she just kind of appears randomly to take victims or just hiss at the screen where as the other one she's a full blown lesbian vampire sex pot.
Also in the film Dracula takes a crazy woman named Maria (Paca Gabaldón) and turns her. She really only gets one scene as a vampire before she's destroyed in the films finale. Her role for most of the film before that is to make random orgasm like noises in a room whenever she's on screen.