KÅsei and Nagi perform a set piece written for piano four hands. During the performance, KÅsei competes with Nagi to see if she can keep up with him. As Nagi believes that she understands KÅsei on a deeper level, this pushes her to perform with all her heart. After they end their set piece, the audience is blown away with their performance. While backstage, KÅsei is confronted by Takeshi, who is jealous that KÅsei teamed up with Nagi, otherwise known as his little sister. Takeshi demands KÅsei the chance to beat him in an upcoming piano competition. KÅsei visits Kaori on the roof of the hospital to find her passion for music awakened, since she listened to KÅsei and Nagi's performance from her phone. KÅsei challenges Kaori to perform one more duet with him.