Collier (Brown) enters prison, having been found guilty of killing her husband. She is introduced to the beautiful occupants of her cell, doing time for crimes ranging from political insurgency to heroin addiction. The women often clash, which leads to their torture by sadistic guard Lucian (Kathryn Loder). The torture ceremonies are viewed by an impassive cloaked figure.
Collier’s cellmates Alcott and Bodine (Collins and Woodell) plan to escape. Collier and another cellmate Ferina (Gina Stuart) agree to go along. Assisting is their other lesbian cellmate Grear (Pam Grier), though doubts exist Grear’s heroin-addict girlfriend Harrad (Brooke Mills) will be equipped to escape.
Ferina, Alcott, and Bodine break from the solitary-confinement sauna and take their revenge on Lucian. The escapees wield guns, attitude, and sexuality to free themselves.
During their escape, they round up various personnel from the prison as hostages, taking elegant prison warden Miss Dietrich (Christiane Schmidtmer), sympathetic prison medic Dr Phillips (Jack Davis), and two local men regularly allowed access to the prison to sell market produce, Harry (Sid Haig) and Fred (Jerry Franks).