Three hundred years have passed since the fate of nations was decided by "battle competitions," in which knights fought to win or lose by shattering the life stones attached to each other's helmets, instead of wars. Nina was born in a village that produced excellent knights, but she was not able to use a sword as well as the other girls around her, and she lived an unhappy life. However, a knight named Licht suddenly recruits her into the knighthood, saying, "You are the one I have been looking for."