Kokoro Ayase works as a school nurse, admired by many men for her elegant and refined demeanor. Despite her poised appearance, she harbors personal struggles—her experience with men is limited, and she has never reached orgasm. While she occasionally discusses sex during her classes, her lack of firsthand knowledge makes it difficult to go beyond superficial explanations, leaving her frustrated in her inability to convey deeper understanding. At the same time, she deeply desires to learn more about sex. She also faces dissatisfaction in her married life, as her intimate moments with her husband are dull and unfulfilling.