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.

Arata Kaizaki is 27-years-old and unemployed. He quit his prior job after working for the company for 3 months. Arata Kaizaki decides to take part in a research program. He takes medication that makes him look younger and he is to attend high school for a year. There, he falls in love with female high school student Chizuru Hishiro.

With dreams of diving abroad, Tsuneo gets a job assisting Josee, an artist whose imagination takes her far beyond her wheelchair. But when the tide turns against them, they push each other to places they never thought possible, and inspire a love fit for a storybook.