The world is divided into two clans: Humans and the Winged. Between these clans, for many years a war raged, until a truce was signed. However, Humans still envy the Winged's ability to fly. The power of the Winged came from the incarnation of the Flower God: every century the Flower Goddess and her beloved incarnate as a pair of lovers; after a kiss, the lovers dissolve into dust, granting the Winged the ability to fly. Humans created a city capable of rising into the heavens; flying without dust is impossible, so they need the incarnation of the Flower God.