Kyuha, a strong-willed and slightly selfish older sister, and Chiharu, a quiet and weak sister. The two were having tea in the living room and complaining about each other's boyfriends. When she heard that her boyfriend's sex was too intense from Chiharu, Yuu felt a little jealous, and her interest in him grew. So Yuu asked Chiharu, "Should we exchange boyfriends?"
