43-year-old Nishina Sayuri is a housewife. Her husband frequently travels for work, leaving her to live almost like a single mother. On lonely nights, she finds herself touching her pussy. One day, her son catches her in the act. Unable to control her arousal, she ends up calling her son into her room. If her husband were to find out, it would be disastrous. Their secret is now trembling on the edge.