Six thousand years before Sora and Shiro were even a blink in the history of Disboard, war consumed the land, tearing apart the heavens, destroying the stars, and threatening to wipe out the human race. Amid the chaos and destruction, a young man named Riku leads humanity toward the tomorrow his heart believed in. One day, in the ruins of an Elf city, he meets Schwi, an exiled female "Ex-machina" android who asks him to teach her what it means to have a human heart.