Twenty years ago, Reina lost her husband and since then has devoted herself to raising her son Tatsuya, working tirelessly to support him through his studies. She helped him get into university and eventually become a successful working adult. In gratitude, Tatsuya surprises her with a hot spring trip. Seeing her genuinely happy and excited warms his heart, but another feeling begins to stir within him. He resolves to confess the truth—he is in love with his mother Reina, not just as family, but as a woman.