The place where older brother Satoshi brought her was the private residence of a high-ranking member of the militant group known as "Ikebukuro Kitchi Baka Ichi-dai," also known as IKBI (Ikebukuro Kitchi Baka Itidai). As a condition for joining the group, members are required to become models for an underground illegal website operated in secret, and without hesitation, the brother offers up his younger sister. Unaware of the truth and left alone in a stranger's house, the younger sister is soon dragged into a brutal and merciless sexual hell.