An otaku college student who started living alone when he entered college. Her sister, who was jealous of such a man, started coming and going in and out of the room frequently. One day, her brother's friend and sister ran into each other. A younger sister who seduces him, who is as insidious as her brother, with a panchira and enjoys his reaction. Her sister, who enjoys teasing her clumsy older man, gradually escalates her behavior and destroys her friendship with her brother. Her younger sister, who has awakened to her abnormal proclivities, will involve even her older brother and seek her mental pleasure.
