Absent-minded schoolgirl Yoriko Kusumoto only has eyes for Kanako Yuzuki. After planning for their summer trip, their journey comes to a premature and brutal end when Kanako is found severely wounded on train tracks and Yoriko in tears on the station's platform. Shuutarou Kiba, a detective who happened to be on the train that hit the girl, takes up the investigation. However, he discovers that the mystery behind this case is intertwined with an intricate network of deceptions involving the Yuzuki family, especially its most prominent member, Youko Yuzuki—a famous actress and Kanako's sister.
Although Kanako survives after surgery, her critical state prompts Youko to entrust a doctor, Dr. Koushirou Mimasaka, to take care of the girl in an ominous, box-shaped facility in the forest where she will receive experimental treatment. But soon after, on a night where Kiba and Yoriko visit Kanako, the convalescent suddenly vanished. Now searching for her whereabouts, the burden on Kiba dramatically grows when he learns about other gruesome discoveries: limbs of young girls in boxes. Kiba is suggested by a colleague that the macabre findings are related not only to Kanako's disappearance but also to the truth behind her sister. As the investigation continues, the detective—enlisting the help of his partners Tatsumi Sekiguchi and Akihiko Chuuzenji—has to find a way to solve this series of crimes and find Kanako back.