Based on a series of light novels written by Tanaka Yoshiki. The story revolves around Ryōko Yakushiji, a brilliant 27-year-old elite investigator with the Tokyo Metropolitan Police. Together with her subordinate Junichirō Izumida, the two often investigate bizzare and supernatural cases. In addition with the paranormal, Ryōko also has a longstanding rivalry with Yukiko Muromachi, another talented police investigator.