Detective Numata, who is pursuing an organization engaged in the illegal trade of human organs, finds a way to infiltrate the group's secret headquarters. There, he sees the horrific figure of a man having his organs removed while still alive. However, when another detective, Tosaka, makes the mistake of trying to save him, their attempt to infiltrate the organization fails. A one-eyed woman named Yoko sees through their disguise and foils their plan. Numata flees the hideout, leaving Tosaka, who is marred by a large burn, behind. Many days later, Tosaka's dismembered body is stuffed alive into a wooden box in the greenhouse of a girl's school. His body is hidden there by the school's biology teacher, Saeki, who uses the greenhouse as a surgical room where he slices open the abdomens of young schoolgirls. In his pursuit of the organization and his search for Tosaka, Numata visits a middle-aged man named Nakanishi, who had raised Yoko and Saeki's siblings after taking them from their abusive mother, to get information about the background of the two of them. He locates the school where Saeki is hiding, and goes to confront the cursed siblings.