Toshio's younger brother, who was abused by his older sister, Runa, when he was watching an adult video, plans to take revenge by stealing Runa and selling it online, but when it is discovered, Runa's bullying begins. Toshio, who has become Runa's sex toy, can't stand it, and begins counterattacking SEX with senior Yanai and others! Runa became a sex slave for her younger brothers...