Years ago a hero known only as Setsu ended the war between humans, beastmen, and demons in the world of Eclair, and the Human King, afraid of him, stripped him of that life and had him reborn on Earth. He grows up there as an ordinary high schooler, Setsu Suzaki, until his entire class is summoned to Eclair as its new heroes. Nobody recognizes the boy behind the new face, so Setsu hides what he can do while looking for his old comrades and for whoever restarted the war he already finished once.