“My mission is to bring happiness to everyone with my singing.” Vivy was created as the world’s first autonomous humanoid AI and works at the NiaLand theme park. Her mission is “to make everyone happy with her singing.” While she is singing on stage, she comes into contact with an AI that calls himself Matsumoto. Amidst her confusion, he asks for her help to rewrite history together, in order to stop the war between AI and humans that will happen one hundred years later.