Several years had passed after Walpugis Night, consecutive bizarre murder cases occurred in the metropolitan. The discovered dead bodies are couples considered to be murdered during sexual intercourse. The women didn't have external injury, but men were completely burned and carbonized except certain parts... male genitals. To solve the mysterious incident, a special detective team called Tokken was deployed. In these members, there was Imari who had experienced Walpugis Night.
Investigating the incident, they found a mysterious word Spear of Longinus, and strange cult group were relating to the incidents.