Yuzuru, who enrolled in a prestigious boarding school famous for table tennis and was living a life immersed in club activities with no immunity to women, returns to his parents' home for the first time in a while. Meanwhile, Yuzuru's older sister Ai also returns to her parents' house after a quarrel between her husband and wife. While she was under stress, Yuzuru learned during a conversation that Yuzuru was still a virgin and seduced her and made fun of her, but she took it seriously. term true