A group of 99 female inmates at an island prison endure the wrath of a sadistic superintendent (Mercedes McCambridge) while 500 male prisoners under the supervision of their warden (Herbert Lom) suffer similar indignities. These worlds collide when the female prison becomes a brothel. Luciana Paluzzi, Rosalba Neri and Maria Rohm also make appearances in this Spanish sexploitation shocker from legendary director Jesus Franco.