Married woman Rei was suffering from sexual frustration and eventually made a move on her husband. However, he coldly rejected her, saying she wasn't satisfying, leaving Rei deeply shocked. Determined to improve, she began vaginal training that night, but accidentally got caught by her doctor father-in-law. Claiming he could offer precise guidance, he agreed to help her. Instead, he applied an aphrodisiac on her and took advantage of her completely. From that day on, Rei became emotionally drawn to her father-in-law, sinking into the forbidden pleasure of their illicit affair. Overcoming her pride as a married woman, Rei awakens to a new, intense desire.