The story happens to a boy named An, who is in high school in Constellation City. He lives an ordinary life. But one day, something unfortunate happened, and countless meteorites of unknown origin crashed into the city. The city is gripped by fear. Finally, Ann woke up from her dream. He realizes that everything that happened was a dream. In real life, he still lives an ordinary life. However, since then, every time he closed his eyes at night, he would re-enter the apocalyptic dreamland, and it was this dream every time. He began to realize that he had abilities in the dream world that ordinary people could not possess, so he prepared to save the world in his dream alone.