A lounge singer with no memories of tomorrow is asked to destroy her own future to save humanity from a war that hasn't happened yet. Vivy doesn't ask whether she should do it, or whether she can trust the ghost telling her to, it asks what it costs to be the only thing standing between two worlds that both think they're fighting for survival. The OST doesn't just underscore the story. It is the story, every song a different version of what sacrifice sounds like.

Vivy is the world's first autonomous humanoid AI, built to perform as a singer at NiaLand, a theme park run on AI. Her mission is to make people happy with her voice, yet she draws small crowds and dreams of reaching the park's main stage. One day an AI named Matsumoto appears and says he has come from a century in the future. He wants her help rewriting history so that a coming war between AI and humans never happens. What begins there is a journey lasting one hundred years. A sci-fi drama with action, thriller and music elements, it weighs a songstress's own mission against the fate of the future.