One day, Hiroshi's mother's friend An's family came to visit. Although they had known each other in the past, Hiroshi found Anzu's huge breasts and voluptuous body to be unpleasant to Hiroshi. Hiroshi gradually becomes unable to control his sexual desire, masturbates in An's underwear, and plays with his body while his son is away. Furthermore, Hiroshi's behavior escalates, and finally...