Kim Ji-su is a 31-year-old single woman who once wanted to become a famous pianist like Horowitz. Her dream was shattered but she was able to go on by teaching children to play piano. One day, she discovers a young boy Gyung-min, is a musical genius. She starts to give him intensive music lessons, preparing him for competition, but it does not turn out well. But later, when all seems lost, Ji-su is utterly shocked when she realizes that Gyung-min carries a secret that will change her life forever.
