FEMALE PRISONER SCORPION: JAILHOUSE 41

Nami Matsushima (Meiko Kaji) is being kept bound in an underground solitary confinement cell, where she fashions a shiv out of a spoon by holding it in her mouth and grinding it against the concrete floor. The prison's chief warden, Goda, is to be promoted to a higher post shortly. When an inspector visits the prison, Matsushima is brought out of confinement for one day. During the inspection, Matsushima attacks Goda and slices his face. The other prisoners start to riot, but it is quelled by the guards.

The prisoners are punished by being sent to an intensive labour camp. Believing that Matsushima may inspire the other prisoners to revolt, Goda assigns four guards to publicly rape her. On the way back from the labour camp, Matsushima is in a van with six other prisoners, Azama (Eiko Yanami), Miyako, nicknamed "Chibi" (Kuniko Ishii), Noda (Hiroko Isayama), Oba (Kayoko Shiraishi), Oikawa (Yuki Aresa), and Yasugi (Yukie Kagawa). The other prisoners beat Matsushima bloody, knocking her unconscious. The guards are alerted that Matsushima is feared dead. When they stop the van to inspect, Matsushima strangles and kills one guard, and Oba and the other prisoners capture the other guard and blow up the van. When Goda sees the wreckage, he sends search parties after Matsushima.

The prisoners escape to an abandoned hut near a village, where they decide to wait for nightfall and steal new clothes to escape in. Oba reveals her crime: when she found her husband cheating on her, she drowned her two-year-old son and killed her unborn baby by stabbing herself in the stomach. In the village, the prisoners find a mysterious old woman wielding a dagger. A surreal sequence follows in which a narrator reveals the crimes for which each prisoner was jailed - Oikawa for strangling her lover who was abusing her son, Azama for poisoning her married lover's wife, Yasugi, a prostitute, as an accessory when violence broke out amongst her jealous johns, Noda for committing arson against people she envied, and Chibi for killing her father in self-defense as he tried to rape her. The old woman gives Matsushima her knife before she dies; her body then turns into leaves and is blown away by the wind.

Oikawa sneaks out of the hut and into her nearby family home, where she is reunited with her son, but finds two prison guards waiting for her. They offer to free her if she reveals the others' locations. Distraught, Oikawa leaves. One guard follows her while the other returns to Goda. Matsushima kills the guard following Oikawa. During the scuffle, Azama is shot in the stomach accidentally and dies shortly afterward.

A tour bus passing through the region is warned by prison guards to look out for the escaped prisoners. Three sexually aggressive men from the tourist group find Chibi returning from the river, gang-rape her repeatedly, and then throw her off a cliff. The other prisoners find her body and chase the men back to the tour bus, which they hijack. Oba and the other prisoners torture, strip and bind the three men and menace the other passengers.

Another surreal sequence shows the prisoners being ostracized by society, for which they are now taking revenge. As the bus approaches a checkpoint, Oba throws Matsushima out of the bus to serve as a decoy. Matsushima is captured, but Goda's men arrange a roadblock in front of the bus, including a flatbed truck with Oikawa's son and elderly parents on it. The bus is stopped and Oikawa rushes out to meet her son. As the guards try to catch her, she is shot by snipers. Oba orders the prisoners to kill the hostages. She kills the bus driver and commandeers the bus, scattering the guards and escaping the roadblock.

By nightfall, the bus is surrounded by the police. Goda sends Matsushima to the prisoners to learn the hostages' status. Matsushima lies and says the hostages have been killed, and the police lead a charge on the bus. The prisoners push the three rapists off the bus, where they are killed in a hail of police bullets. In the ensuing fight, all the prisoners except Oba die. Oba is injured and set to return to prison in the same vehicle as Matsushima. Goda orders the guards to stage an escape attempt by Matsushima in order to kill her. The guards stop at a junkyard and are about to shoot her when Oba saves her by biting the guard on the neck. Matsushima kills the guards. The next morning, as they flee through a junkyard, Oba succumbs to her wounds and dies.

Goda is promoted to a higher position in Tokyo, where Matsushima tracks him down and stabs him to death. The film ends with a fantasy sequence in which all the female prisoners of the jailhouse, wearing their striped prison dresses, run free through the city, passing Matsushima's knife from woman to woman.

After a series of betrayals and losses among the escapees, Matsushima confronts the warden and secures her vengeance before disappearing into the night.

The ending cements Matsushima as both survivor and avenger, closing the chapter on her tormentor while affirming her refusal to be broken by the system. Her escape into the unknown is less a victory lap than a final assertion of autonomy against a world set on crushing her spirit. The film’s conclusion is both defiant and haunting, leaving the scars of institutional violence and personal resilience etched in memory.