Turning the clock back a century, AIs are already a part of human civilization, designed with certain goals that must be completed during their lifespan. Vivy, the world's first self-aware AI, is a singer entrusted with spreading joy via her singing. She struggles to pour her heart out into her performances in a theme park where she seldom has a good audience, bound to repeat it day after day—that is, until a sophisticated AI from the future comes before her and enlists her aid in ending a horrific war a hundred years in the making. With no time to digest the news that turns her life upside down, Vivy is thrown into a century-long quest to avoid disaster.