An old scientist creates a robotic girl named Key. She lives with her creator and his assistant and is an outcast among her classmates. Key's life is turned upside-down when the scientist dies. His last words to Key are instructions telling her how to become human: win the love of 30,000 people. Key goes to Tokyo and stays with an old friend, Sakura. After seeing a performance of the famous idol singer Miho Utsuse, Key decides the best way to make 30,000 friends is to become an idol singer. Can Key become a real girl or will the secrets of her dead creator kill her first?