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 stars, and even 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 Shuvi, a female exiled 'Ex-machina' android who asks him to teach her what it means to have a human heart.
