Sayaka Kudo (Kasumi Arimura / Mochika Yamada) is a 2nd grade high school student. She is a gal who wears miniskirts and has her hair dyed blonde. Even though she is a high school student, her actual academic grade level is on par with 4th grade elementary school students. During the summer, Sayaka attends a private institution. There, she meets teacher Tsubota (Atsushi Itô). Besides her mother (Yô Yoshida), teacher Tsubota is the first adult to praise her. Sayaka begins to change. She studies hard and eventually passes an entrance exam for Keio University.