In this adult role-play, the narrator is constantly ordered around by aggressive classmates, who eventually invade his home and refuse to leave. His beautiful adult sister Natsuki tries to defend him, but her protest only enrages them. They gang-rape her in a four-person scene and cover her face with semen while laughing at her. The abuse continues for a full week as the bullies turn the house into their hangout. Watching his proud sister overwhelmed into a vacant orgasm trance fills him with anger and jealousy—yet, to his horror and shame, it also gives him an erection.