Aria, who decided to attend a vocational school in Tokyo. She has no money and hates part-time jobs. She came to Tokyo, asking her brother to let her stay at his place for a while. Her younger sister is a plain, NEET country girl. Her brother, who thought he should do something about it, decided to make his sister grow up by having her wear cute mini skirts and lewd underwear. The younger sister who changed her clothes was unrecognizable... she was lewd and erotic... and he couldn't help but even train her sexually!