Piano prodigy Kousei has been traumatized and unable to play ever since his mother's death. He has a momentous meeting with violinist Kaori.
Kousei accompanies Kaori to a violin competition and is overwhelmed by her talent and spirit, but jealous when she shows a fondness for his friend.
On an outing to a cafe, Kaori convinces Kousei to play the eatery's piano. She then gets him to agree to accompany her for her next competition.
During the violin competition preliminaries, Kousei experiences serious doubts and difficulties, but Kaori lends her patient encouragement.
Kousei and his friends are alarmed when Kaori ends up in the hospital. Kaori and Kousei have been disqualified from the music competition.
Hearing a recording of his own playing has a strong effect on Kousei. Kaori continues to insist on making Kousei her accompanist.
Kousei has learned the piece for the competition, but he is overwhelmed by anxiety and winds up collapsing. A meeting with Kousei's old rivals looms.
At the piano competition, Kousei's rival makes a big showing, inspiring Emi, whose own performance has a great effect on Kaori.
Emi is unable to communicate her emotions to Kousei after her performance. As the moment of his performance arrives, Kousei confronts his demons.
With the pressure of his trauma weighing upon him, Kousei battles against his insecurities during his performance, with his friends cheering him on.
After Kousei's performance, he is greeted by an old friend of his mother's. The winner of the piano competition is announced.
Kaori invites Kousei to accompany her as she plays at a gala concert. The piece she chooses holds a lot of emotional importance for Kousei.
When Kaori fails to show up for her performance at the concert, Kousei takes the stage by himself to play a piano version of a favorite piece.
Kousei learns the true reason why Kaori failed to show up for the concert. Tsubaki begins to realize the nature of her feelings about Kousei.
When Tsubaki finds out about Kousei's plans to leave home, her feelings for him come even more into focus, especially for her boyfriend.
Kousei takes on the role of teacher for the first time ever. Kaori comes to see Kousei and delivers surprising news.
Tsubaki asks Kousei to join her in visiting Kaori at the hospital, but he's not sure if he can handle it. Nagi tries to boost Kousei's morale.
Kousei accompanies Nagi in a performance at Kurumigaoka Junior High, but when he gets inspired, things take an unexpected turn.
Inspired by Kousei and Nagi's performance, Kaori decides to have a dangerous surgery so she can play with Kousei once again.
When Kousei finds out that Watari is at the hospital with Kaori, he changes his plans about visiting her, frustrating Tsubaki in the process.
When Kaori's health takes a downturn, it sends Kousei into a depressive spiral that pushes him away from playing the piano again.
Kousei arrives at a couple of very important realizations about himself and his music, and gives it his all for Kaori's sake.