A wife named Hikaru, who lives amicably with her husband and his parents, is bothered by her mother-in-law's constant desire to see her grandchild. However, Hikaru is secretly troubled by her inability to be positive about sex. When she consults her father-in-law, he admonishes her, saying, "You don't yet understand the pleasure of sex." For the sake of her husband and mother-in-law, Hikaru decides to accept her father-in-law's "close training"...