The older sister is a stewardess who can't stand it.

A younger brother who is a 5-year judicial ronin and stays at the house of his brother, a pilot, and his sister-in-law, Emiri, who is a stewardess. He masturbates while watching Emiri change clothes, watching her having sex with her brother, and fantasizing about it. Finally, he even peeks in and has sex with his boss, which he called training at the airport!