In 1968 a French film distributor was looking for a short film to bundle with his next release and make up for the feature's rather anemic run time. He hired a young film-maker named Jean Rollin to produce the necessary picture. Rollin's resulting effort, Le Viol de Vampire, had two major flaws: firstly that at 45 minutes it was a quarter-hour longer than planned, and secondly that it was rather better than expected. Good enough in fact for the distributor to find more financing so Rollin could expand it into a feature itself.
I imagine that most film-makers in this situation would look for ways to extend the existing scenes in their script, and to insert new ones into the narrative so that the basic plot was unchanged but it took longer to deliver. Rollin was not most film-makers. Instead, he filmed a second, self-contained film, picking up where the first left off and using the same characters. I don't know his motivations for this. Perhaps he felt the existing narrative's pacing and tone would be ruined by trying to wedge extensions into it at this late stage. Perhaps he just thought it would be easier.
Now in principle I guess Rollin's approach could work, if the new material followed on from the original in a convincing manner. Alas, in this case it does not. In fact, it actively works against the original.
Rollin's original short film concerns four sisters who live in a derelict chateau. The local villagers - and the sisters themselves - believe the quartet to be vampires. However, three outsiders from Paris do not agree. One of them in particular scoffs at the very idea, and he's not short on evidence to support it: only one of the young women drinks blood (and that from birds), while another is the sole sister to exhibit any fear of sunlight (despite all four saying it could kill them). These and other factors seem to indicate strongly that the entire 'vampire' story is a collective fantasy.
The new material suddenly reverses course. The sisters are vampires after all, and there is in fact an entire secret community of blood-drinkers, led by a Vampire Queen. Queenie has many plans and schemes afoot - not that the film will ever explain what they are - while many of her subjects chafe at her rule and at their undead existence. Material like this could work as a story, it's true - provided you could surmount the cognitive whiplash when compared to what came before - but Rollin had neither the skill as a writer nor the budget as a film-maker to do justice to it.
Behold the Queen's "throne room"
The first half of Rape of the Vampire is sleazy and barely coherent, but it has some nice shot composition and strongly evokes its mood. The second half is even more sleazy, completely incoherent, and doesn't seem to know what mood it is aiming for. Not recommended.