The Mifune and Satoda families are still engaged in a betrothal arrangement. After her parents pass away, she is training to be a bride at the Satoda household and realizes that her fiancé, Ryota, has become sexually awakened. Ryota is flustered by her big breasts, just like a child. Seeing this, she feels a deep affection for him. She becomes addicted to the pleasure of taking the virginity of naive boys one after another...