The story follows a series of bizarre murders of schoolgirls who have been dismembered and stuffed into boxes. The private investigator hired by a missing daughter's mother joins forces with an antique book seller and others to unravel the murder spree.

[Source: Anime News Network]

A side story that reveals the investigative notes that Atsuko, the younger sister of the main character Akihiko Chuzenji, wrote about the brutal dismembering incidents in the main story.

[Source: Anime News Network]