Kai Yuki, a college senior studying social welfare psychology, struggles to get any job offers. One day, he sees a girl playing the violin on campus.
Tasked with assisting Sae, Maho asks Kai for help. After hearing about Sae’s past from her friend Akane, Kai tries to recover the violin she sold.
Kai arranges for a semi-pro student orchestra to hold an audition for Sae. She is overjoyed when she passes, but a complication soon arises.
At Keita's suggestion, Kai and his friends start keeping a shared diary. Later, Maho stuns Kai by telling him they should take some time apart.
In celebration of Akane’s job offer, Keita invites the Orange Group members on a camping trip. Kai runs into Maho at a café, but Sano soon shows up.
When Sae struggles to find a job that piques her interest, Kai suggests that she play piano. She asks her mom for lessons after seeing a job listing.
An old friend from when Sae studied abroad in America asks her out on a date. Despite his jealous feelings, Kai helps her calm her nerves.
Sae's fear of getting hurt causes her to act coldly toward Kai and anger him. Akane invites the Orange Group to the beach to help them make up.
When her mother gets invited to join a German orchestra, Sae must decide if she’ll move with her or stay in Japan. Later, she runs into an old friend.
After Sae's hearing worsens, her mother suggests surgery for the first time. The Orange Group hangs out one last time before Shohei leaves for Tibet.
Life goes on for the remaining Orange Group members. After Shohei returns for graduation, Kai admits over drinks that he still has feelings for Sae.
