Natsume, who lives with her father-in-law at her husband's parents' house, has let Kokoro go wild because of her father-in-law's kindness. When her husband is away, her father-in-law takes advantage of her and bares his fangs. At first, Natsume resists, but she gradually falls for her father-in-law's relentless attacks and precise caresses that set her frustrated body ablaze...