Paul Beaumont is a success with his paintings of human terror. Feeling exhausted he goes to work on one final masterpiece. He scares a model to death and paints the ultimate terror. The ghost of the woman, however, urges him on to work until he collapses.
The couple of John and Alice gets lost in the countryside. They come to the home of Senor Gato who lives in the company of cats. Or rather cat-beings able to take on human form as well. Alice is transformed into a cat and John accidentally kills her.
Elderly Dr. Gordell drinks a potion which transforms him into strong, primeval cave-man. As such he roams around and murders innocent passers-by. Gordell’s daughter and his assistant Roger can track him down and get him engaged in a death-match with a circus gorilla.