To end the bitter war between their countries, Roh, prince of Carna, has been engaged to Sukur, princess of Horn. The two of them meet for the first time in the Garden Sphere, a secluded palace where they are to live together for one year until they appear before the people.

Neither of them has any romantic interest in the other, but they decide to pretend to be a loving couple in order to keep the shaky alliance between their countries from dissolving. However, neither of the two children has any idea how couples act, giving them only a single year to discover it for themselves and perfect their act of romance, starting with simple acts of love and working their way up from there.