Sayaka Kudo (Kasumi Arimura) 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. Besides her mother, 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.

Biri Gyaru is a 2015 Japanese movie directed by Nobuhiro Doi. It's based on a novel by Nobutaka Tsubota's titled "Gakunen Biri no Gyaru ga Ichinen de Hensachi o Yonjuu Agete Keio Daigaku ni Gen'eki Goukaku Shita Hanashi". In it, he recounts the experiences of one of his former students who made drastic changes to her academic life over the span of one year.

Blonde-haired “gyaru” Sayaka has always been more interested in fashion than her studies. Because of this, she now has the scholastic aptitude of a 4th grader as a second-year high school student. However, when she visits a cram school, lecturer Mr. Tsubota recognizes her innate intelligence. After an informal discussion, and with the support of her family, Sayaka becomes determined not only to improve her grades, but to spend her final year of high school working hard toward getting accepted into prestigious Keio University.

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