During the Heian era, a prestigious statesman had two children who desired to be the opposite sex. Lady Kira was a resolute and determined girl, while Lord Kira was a delicate and attractive boy. Due to their individual personalities, their father arranged for Lady Kira to be brought up as a boy and Lord Kira as a girl. The manga takes inspiration from a novel written during the end of the Heian era titled "Torikaebaya Monogatari".