In order to find out why his son and wife are unable to have children, the father-in-law spies on them having sex...and discovers his son's immature sexual acts! Enraged, the father-in-law uses Kanna's body to demonstrate a "sex lesson" to the couple. Kanna is easily brought to climax by the father-in-law's cunning techniques, who knows the female body well. The couple was taught the tricks of making a baby, but Kanna's lewd body gets the father-in-law in the mood. The father-in-law's instruction becomes more and more extreme, as he gets close to Kanna, performs intense cunnilingus on Kanna, and forces her into sex. Kanna is gradually drawn into the intense, intimate sex of her father-in-law, which is different from that of her young husband...