Natsume, who lives with her father-in-law at her husband's parents' home, has forgiven her heart for his father-in-law's kindness and becomes vulnerable. Natsume's father-in-law bares his fangs, taking advantage of her husband's absence. At first, Natsume resisted, but she gradually fell for her father-in-law's relentless torture and precise caresses that set her body aflame with frustration.