Scorpion: Double Venom (1998)

Nami Matsushima, a former doctor, is put in prison for murdering one of the men who raped and killed her sister. Now, faced with violent and lecherous prison gangs, an aggressively amorous warden, and with a friend on death row, Nami must steel herself for a ten year stay in one of Japan's toughest women's prisons.