Kosei Arima was a piano prodigy until his cruel taskmaster of a mother died suddenly, changing his life forever. Driven by his pain to abandon piano, Kosei now lives in a monotonous, colourless world. Having resigned himself to a bland life, he is surprised when he meets Kaori Miyazono, a violinist with an unorthodox style. Can she bring Kosei back to music, and back to life?