A journalist and his mistress photographer study the behavior of killers maniacs, collecting material for a book. They are particularly interested in places where crimes are committed. They go on an expedition and inadvertently take another couple to the car. It would be better if they did not do this, since the overgrown sullen fellow, followed by a squeaky fool woman, is a real crazy psychopath. The luckless criminologists will test the "behavior" of the studied population on their own skin.