Nino makes two promises when she was little: the first was to her childhood friend and first love, Momo, and the second was to a boy who was good at writing music, Yuzu; she sings in hopes of one day seeing them again.

Nino and Momo get along wonderfully and sing together; Nino believes that, as long as Momo was by her side, everything would be fine; when he suddenly leaves her side, Nino goes to the beach to scream and finds Yuzu.

Nino begs for Miou to coach her in singing; Nino feels defeated because she sees how far behind Miou she is in singing technique; that night, while watching TV, Nino happens upon a certain discovery.

Nino can't stop blaming herself for what happened to Yuzu while he's determined to make her sing for him.

Nino and Momo finally cross paths, but their reunion is cut short when Momo lets his past get in the way; Yuzu is waiting for Nino to perform his music.

When Nino is given Momo's damaged guitar, she is determined to learn how to play; meanwhile, Yuzu's feelings grow stronger.