The main character of hentai Toyah-kun is an ordinary young man who transfers to a new educational institution and begins to live with relatives. Upon arrival, he discovers that his new teachers are four attractive women: English teacher Rio Onadera, math teacher Nagisa Shiono, biology teacher Amane Amamiya, and another teacher, Sarah Akizuki.

This story is about a family that has been cursed by an ancient curse. Because of this, no daughters were born in the family, and it was only thanks to the help of the Higetsu clan that this disaster bypassed the family for three generations.