Three months after Nanjo Rena took up her new post at a private high school, a series of bizarre explosions have been occurring. Principal Murai, who was lobbying city councilman Matsuda for the establishment of a university, was concealing the incidents and pursuing the culprit. Leading the investigation was Chiba, a physical education teacher and Rena's lover since her student days. One afternoon after school, Rena was taken to a club by the principal, where she was plied with alcohol and taken to Matsuda's place...