Yura Yamato, a shy girl with little confidence, enrolls into the prestigious Stella Women's Academy, where she struggles with making friends. After finding her arranged dorm roommate, Sonora Kashima, is out visiting her family, Yura looks around the room and is surprised to find an array of guns, military items and action movies. Elsewhere, the curious C3 Club discusses how best to recruit new members. Whilst fetching some equipment from Sonora's room, C3 member Rento Kirishima discovers Yura becoming heavily engrossed in a Rambo movie and decides to drag Yura to the clubroom. Whilst initially assuming the club is a laid back and ladylike one, Yura is surprised when she learns the club's activities actually revolve around airsoft guns and tactical simulation. After luring Yura back with some cake, the club invites her to try out a Rambo-style game, in which one member, Karila Hatsuse, acts as Rambo whilst the other members, Rento, Honoka Mutsu and Yachiyo Hinata, along with Yura, are the sheriffs trying to take her down. Despite not being able to win, Yura gets a sense of excitement from the battle.