Natsumi (Ai Takeuchi) is forced to work in a steel factory in order to pay off a debt, a factory notorious for employing women with “dark pasts” as slave labor. Tsukada, Chief of Security, places Natsumi in a team of four women led by Atsuko (Nagisa Umeno). When one worker fails to follow instructions, Tsukada rapes her, and Natsumi is next on his list. Natsumi tries to fight the insanity but is hindered by managing director Hideko and factory president Kamiyama. It is up to Natsumi to take on the evildoings of the factory.