Ayumi lost her husband early and raised her only son, Koji, by herself. She was living a modest and happy life, but there is something strange about Koji who has reached puberty. As she ponders what to do, she notices a dream sperm on her underwear. Ayumi, who decided to teach her correct sexual knowledge for her beloved son, began to teach herself sex as a teaching material. However, she began to show her ecstatic expression on her son's high-speed piston.
