Masahiko Yanagiba lost both parents and, in accordance with his mother's will, moved in with his maternal uncle's family, the Wakanaes. Although the Wakanaes' hospitality was heartwarming, he soon discovered why his other relatives avoid them: his "uncle" is actually a woman, while his "aunt" is the opposite. It turns out the couple has taken on the appearance of the opposite gender, leaving Masahiko unsure whether his cute cousin, Shion Wakanae, is a boy or a girl.