Yamato Yura is a shy student starting high school at an all girls boarding school. When she finds her absent roommate’s collection of airsoft guns and action movies, she proceeds to reenact a shootout, to the joy of Rento, who, as a member of the understandably unpopular C3 mock battle club, is looking for members. Failing to convince Yura after butchering her name and continuously calling her a weirdo, the club tries to win her over with a mock battle. Yura is initially hesitant, but seems to begin enjoying the battle as she sees the other girls in action, and begins to imagine the battle as real.
