When Yura Yamato's roommate Sonora asks her to join her club, it quickly becomes clear that the girls of Stella Women's Academy are VERY different. It turns out that she belongs to a club known as C3, whose afterschool activity is playing survival games! It's not a typical teenage girl pastime, but Sonora and her trigger-happy friends are into it. Can Yura join up, stand up, and deliver in the face of friendly fire?