A group of women, suspected dissidents and opponents of the regime, fall into the hands of the military police. They send the women straight to a strict women's prison deep in the jungles of South America. The head of this camp immediately puts them in the notorious cell block 9, where they are to be squeezed for information about their secret underground organization and the names of the collaborators. Dr. Costa, the sadistic prison doctor and torture master, takes care of the women using perverse and perfidious torture methods. One of the prisoners collapses under the torture and confesses everything. It is up to the resistance organization to warn the cell in the city before it is too late. By having four of the chained naked women stage a little lesbian orgy, they manage to distract a guard and get hold of the keys that seem to promise freedom. But the fugitive prisoners are hunted mercilessly.