The story, which occurs in Chiba Prefecture and Maihama, follows a highschool boy who participates in extracurricular activities (swimming) and suddenly finds out that he is the only one being able to see things and people others cannot see. Not long after that, he gets suddenly drawn into the center of combat in group of giant robots, where he ends up piloting the robot. But the question which arises is most of all ... what exactly is real of the world he is in?