Nao, the daughter of the Kiritani family, has a daughter-in-law who is quite a bit older than her. When the day of their meeting arrives, she is astonished at how young she is, but Nao is excited by Ryohei, her daughter-in-law, who has ulterior motives, just like a boy. While her parents are away, she lets him touch her G-cup tits and pussy, and gently sucks his erect penis. Then, they can no longer control their sexual desires and have an untimely first night together...