Based on the infamous "Concrete-encased high school girl murder case" that took place from November 1988 to January 1989 in Japan. Junko Furuta, a female 17 year old high school student, was kidnapped and confined in a house by four other male high school students (all juvenile) in the Ayase district of Adachi-ku, Tokyo, where she was repeatedly raped, sexually humiliated and tortured in an extremely brutish manner for 41 days before she finally died after a particularly severe beating. The boys hid her body in a drum and filled it with concrete, but the body was nonetheless discovered a few months later.