A normal 10-year old girl, Yuu harbours a secret crush for her childhood friend [Toshio Ootomo](https://anilist.co/character/84277/Ootomo-Toshio). Given the ability to transform into a 16-year old girl, she is made to fill in for the absent [Megumi Ayase](https://anilist.co/character/38802/Ayase-Megumi) to sing on TV. Giving her name as Creamy Mami, she becomes an overnight hit.