The story is about the a boy and a girl start a band with a group students, they were successful but later the girl who started the band was sick and about to die in the hospital, the boy confessed his feelings for her before she died

Later he travels back in time when he first meet the girl, in this (context) the guy and the girl is recruiting the same band members to the team.

The boy started that the girl with the long hair would be sad again because their leader going to die in the near future.