After the final battle against the eighth class card, Gilgamesh. Kiyomi, Illya, and the rest of everyone was ready to relax with what was left of their summer break. But things take a turn for the worst when Miyu is kidnapped by two people, and they're all sent to a parallel world. When Kiyomi is reunited with Gil, the boy who caused them a lot of trouble, she decides to trust him again in order to save her friends. Soon enough, she begins to fall for the young boy who is also known as the Heroic Spirit, Archer.