Onigashirajima Joshi Keimusho

On a secluded island known as Onigashira stands a prison for women. In this prison, inmates are being methodically raped and tortured by wardens. The player is invites to witness the events that take place in the prison from the point of view of five characters: two prisoners, the lovely 23-year-old Chika Kanzawa and the innocent teenager Miki; the sadistic female warden Enko, the police officer Otonashi Youichirou, and a mysterious man known as Seiki, who has his own agenda.

[From Moby Games]