A father, older brother, and younger sister live in a housing complex on the outskirts of Tokyo. The sister (21) has been attending university and has always supported the family as a mother figure. The brother is a 32-year-old NEET who never left the family home. The sister has been handling her brother's sexual needs for the past year. She harbored the secret of being 'highly sensitive all over her body' and, despite knowing that having sex with her brother was wrong, she couldn't help but feel good about it.
