The story takes place in the year 300 of the God Century. It mainly tells the story of Yuuki Yuna, a second-year junior high school student. She lives a peaceful life in school every day, attending classes, participating in club activities, and playing with many friends. No matter how you look at it, this is a very ordinary girl's life schedule, but there is only one thing that is decisively different from other children, that is, the activities of the club called "Brave Club" she belongs to. The activities of this club, centered on the head of the club, Inubo Saikaze, are related to the mysterious existence called Vertex, which is surrounded by mysteries. This work mainly describes the activities of the "Brave Club" of Yuna and others.