Her sexual fetishes were twisted by the slovenly older sister next door, a little devil lesbian, and they repeatedly craved each other in the messy room, drooling and sweating profusely. (Nitori, Kojima Miko, BBAN-616)

Miko, a diligent female college student, is constantly bothered by her slovenly older sister, Nitori, who lives next door. In the mornings, Nitori is always hungover and reeks of alcohol; at night, she masturbates with loud, labored breathing, disturbing Miko's studies. Miko sees Nitori as a negative example. However, Miko finally reaches her limit and decides to confront Nitori. This incident becomes the catalyst that completely shatters Miko's values and drastically distorts her sexual desires...