Vivy, the world's first autonomous AI, sings to bring joy to her audience as a cast member of NiaLand, Japan's largest theme park. In this world, AIs have become integral to human life and exist to carry out their missions. One day, out of the blue, an AI claiming to be from the future approaches her, revealing that in one hundred years, advanced AIs will turn on the humans they once served, sparking a violent war to annihilate humankind! When he asks for her help in preventing the conflict, Vivy agrees to ditch the stage and take up the century-long mission against her kind in order to save humanity.