Kae, a young sister, lived alone with her older brother. Their parents had already passed away, leaving behind a massive insurance payout. The brother, unemployed and reclusive, spent his days drinking, indulging in pachinko, and obsessing over sex. One day, he invited her to go to a "happening bar," eventually admitting he wanted to watch her get fucked by other men. Though embarrassed, the helpless sister could do nothing but obey. This work portrays the twisted relationship between a resilient younger sister and her cruel older brother, unfolding into a perverted, gripping tale that captivates the audience.