Katsu receives a phone call from his mother-in-law, Saori, and goes to his aunt Miyuki's house to pick up something he forgot. When he rings the bell, there is no response, so he goes to the backyard and finds Miyuki masturbating with a vibrator while watching TV. Isn't there? ! He was overwhelmed by Miyuki's appearance and tried to run away, but he was forcefully invited into the house. Eventually, Katsu becomes addicted to the charm of Miyuki's voluptuous body.