A secret society "Chaos" that plans to conquer the world. Yukina is a member of "Zeus," an organization that protects humankind from such evil hands. Yukina goes on a search with her partner Ellis to investigate the mysterious island that suddenly appears, but she gets lost on the way. When she was wandering around an isolated island where she couldn't get in touch with the outside world, she was attacked by a female knight who seemed to emerge from the fantasy world.