A scientist taints his mother's scientific experiment with his own drug that transforms pain into a pleasurable experience. Unfortunately for the three women involved in the experiment, the drug works a little bit too well.

The third and final 'Heron Master Ippei' film.

An unprecedented bizarre murderer appears. The first victim is a young woman. Both breasts were cut off. Kyoko Mizuki, a female medical examiner, begins to feel a strange presence around her after attending the autopsy. The second and third murders occurred as if to mock the investigators. The murderer's M.O. was extremely abnormal and ruthless, mutilating the woman's body. Kyoko tries to deduce that the murderer is a psychopath. Emi, a rookie detective, is the first to get close to the killer, but she is trapped in the opposite direction.