Kinoshita Mairu has a cute name and she's apologetic for it, because she's ugly. In fact, she's apologetic for her very existence because she's not cute. Classmates call her "Poison Mushroom" behind her back and even her own brother treats her with disdain. However, all of that is about to change with the help of her transgender mentor/neighbor, Fuwari-chan, and the "school king," Kumada Tenyuu!