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 continue teaching the children to play the piano. One day, she discovers a young Gyung-min, he is a musical genius. She begins giving him intensive music lessons, preparing him for the competition, but it doesn't go well. But later, when all seems lost, Ji-su is completely shocked when she realizes that Gyung-min has a secret that will change her life forever.