Yuu meets a boy with special powers, Uchiyama Makoto. Makoto wants to hog Yuu all for himself, and uses his powers to keep everyone else away from her. Yuu decides to pretend to be obsessed with Mami and starts to ignore Makoto. Makoto wishes that Mami were gone, so he shows up at her concert and everything goes amok!
Yuu is a precocious 10-year-old girl who likes Toshio, a boy, 3 years older than her. One day, Yuu runs into aliens that have trouble with their damaged spaceship. In appreciation for helping them repair the spaceship, the aliens give Yuu a magical stick with one condition; she must keep it secret, otherwise she will lose the special power. In order to attract Toshio, Yuu decides to transform herself into an attractive 17-year-old girl! Yuu, with the 17-year-old figure, happens to be discovered as an idol singer and makes her debut as “Creamy Mami”. But she never could have imagined that Toshio would start to be attracted to Creamy Mami, and not Yuu herself. This is the first and the most popular story of Pierrot's Magical Girls series.