Violinist Kaori Miyazono brings an unexpected demand into Kousei Arima's quiet junior high school life: she wants him as her accompanist. The eccentric musician draws him toward a stage he has avoided since his mother's sudden death, even though his attachment to music has never disappeared.
Once admired for his flawless precision, Kousei earned the nickname "Human Metronome" and won every competition he entered under his strict mother's rigorous guidance. The trauma of losing her left him unable to hear the piano. Now spending his days with friends Tsubaki Sawabe and Ryouta Watari, he still struggles with that loss. Kaori's efforts to bring music back into his life—and a small lie—draw the two young musicians closer.