Arima Kousei won numerous piano competitions while under the strict watch of his mother. He was known as the human metronome during that time. Since the death of his mother, Kousei has been unable to hear the sound of his piano. He then meets Miyazono Kaori through childhood friend Sawabe Tsubaki. Kaori plays the violin and has a free sprit. Since meeting her, Kousei is able to face the piano again. Meanwhile, Kaori holds a secret.
| Actor | Role |
|---|---|
 Kento YamazakiKousei Arima | Kousei Arima |
 Suzu HiroseKaori Miyazono | Kaori Miyazono |
 Anna IshiiTsubaki Sawabe | Tsubaki Sawabe |
 Taishi NakagawaRyouta Watari | Ryouta Watari |
 Yuka ItayaHiroko Seto | Hiroko Seto |
 Rei DanSaki Arima | Saki Arima |
 Yoshizawa RirikaKoharu Seto | Koharu Seto |
 Yuuri OeKousei Arima (young) | Kousei Arima (young) |
 Maharu NemotoKaori Miyazono (young) | Kaori Miyazono (young) |
 Masahiro KomotoNot listed | Not listed |
 Hirotaro HondaNot listed | Not listed |
 Kaori YamaguchiNot listed | Not listed |