Hibiki, who has been playing the piano since his childhood, had an admirer. It was a boy named Ritsu who attended the same piano class. His piano tone is so clear that it is hard to believe that he is the same age as Hibiki, and he spends his days secretly eavesdropping on his lessons. One day, however, Ritsu suddenly disappears from the piano class. There was no sign of him taking part in any contests, and he thought he would never hear him play the piano again. However, when he enters high school, he hears Ritsu's piano tone from the second music room...