Shota receives a shocking confession from his father—the news that he's remarrying his homeroom teacher. Though surprised, Shota doesn't mind the teacher much, especially since she has big tits. However, his father is emotionally distant and uninterested in sex, leaving the teacher frustrated and sexually unsatisfied. With no mother around, Shota begins to enjoy family life to the fullest—sharing baths with her, sneaking into her bedroom, and playing mischievous pranks that slowly bring them closer. An unusual relationship gradually deepens between them.