In order to find out the reason why the son and his wife are not blessed with children, the father-in-law looks into the activities of the two children... Then, his son's extremely immature sexual activity is discovered! - The father-in-law is furious and uses Kanna's body to demonstrate a ``sex course'' to the couple. - Kanna is easily brought to climax by the skillful skill of her stepfather who knows the female body. - The couple learned the tricks of having children, but Kanna's naughty body makes her father-in-law interested. - The father-in-law's instructions become more extreme, and he sticks close to Kanna, performs intense cunnilingus, and forces her to have sex. - Kanna gradually becomes absorbed in the intense intimate sex of her father-in-law, who is different from her young husband...