A doctor—on orders from a sentient brain—kidnaps intimate couples and takes them to his mansion as prisoners. He injects his subjects with a substance to 'enhance' their sexual abilities. The curious doctor then forces his hostages to have sex. While they are making love, he drains a fluid from them, which he needs to prevent himself from transforming into a monster.

The police, led by Inspector Ibanez, are baffled by the murders of several attractive female dancers who all work on a musical TV show that features a horror-themed tableaux. The killings are the work of a masked psychopath with a taste for human blood and there are many suspects…