A police detective known to his colleagues as Yousuke Kobayashi; an inoffensive family man tracking down a serial killer who mutilates his victims by severing their limbs. When the killer sees Yousuke on television he claims to recognize something in the detective and mutilates Yousuke's girlfriend. Yosuke eventually tracks down the killer at which point a new personality called Shinji Nishizono, an arrogant and callous psychopath, emerges and shoots the killer.
From this point onward, the personality of Yousuke is replaced by Kazuhiko Amamiya, a cool-headed, serious criminologist who is arrested and imprisoned for the murder of the serial killer. Kazuhiko's personality fluctuates several times during the course of the story, most commonly switching between Kazuhiko Amamiya and Shinji Nishizono in the early chapters.
It is usually clear to the reader which personality is in control at any given time as Kazuhiko Amamiya is near-sighted and wears glasses, whereas Shinji Nishizono does not require glasses.