While on her way to a new middle school by train, Momoka Sonokawa falls prey to a molester. Fortunately, fellow student Miou Ootori saves her with her dual pistols. Miou, who is the leader of Aogiri Academy's Survival Game Club, also witnesses Momoka's pistol skills and urges her to join. Initially hesitant, Momoka eventually becomes drawn to the group and joins Sabage-bu. Sabage-bu is anything but a typical middle school club, and Momoka quickly learns this. The members' peculiar behavior and eccentricities unsettle her, and some are borderline obsessive. They'll wear ghillie suits in public without a second thought and even bungee jump from the school building. Momoka must not only adjust to a new school environment but also navigate the strange antics of survival game enthusiasts.