After school, the heroine Yui (Kanna Hashimoto) is suddenly surrounded by a group of gyaru girls, and just when it seems like she might get beaten up, they invite her to join a gyaru group called the Hakata Gyaru Alliance (Hagyalen). It turns out that Yui's older sister Ayumi (Riisa Naka) was the first leader of Hagyalen and was a charismatic figure among the gyaru. When Yui returns home and talks about the gyaru group during dinner with her family, an argument unexpectedly breaks out between her father Masato (Yukiya Kitamura) and her grandfather Eikichi (Ken Matsudaira).