A busy mother hires a "rental mom" service. The woman who arrives is Aki, a stunningly beautiful and well-built rental mom. The mother is extremely satisfied as Aki efficiently helps with housework and childcare. The son is captivated by her beauty and starts acting affectionate. However, one day, after being teased at school for not knowing about sex, the son asks Aki to teach him about it. Part of a rental mom's job is to fulfill such requests. Aki agrees and begins instructing the son in the ways of sex. As time passes, the bonds between mother and son, as well as between the son and Aki, grow ever deeper.