Yumi, a seasoned teacher, was trusted by parents and relied upon by her superiors and colleagues. However, she harbored a significant secret unknown to those around her—she had entered into a physical relationship with her student, Okamoto. This affair continued discreetly, carefully concealed from others, without regard for her position as a teacher. Okamoto, still young and deep in the throes of adolescence, driven by desire and new urges, began groping Yumi's body even during class. Under these circumstances, the story unfolds with intense anticipation, revealing how their forbidden relationship evolves.