Misa, who works as a nurse, finds out that her younger brother Ari is hospitalized. Misa is excited to cheer up her cute little brother, but when Ari has his pubic hair trimmed by Misa's senior Nanako in preparation for surgery, his identity as a man is awakened... The next day, Misa hears that Nanako has asked Ari for sex advice, and decides to teach Ari about sex.