A year after their deceased friend Honma Meiko appeared to them, Jinta Yadomi and the other members of the Super Peace Busters decide to write letters in her memory. Attempting to enjoy their summer together, they reminisce about their time together before and after her death.
AnoHana. Movie retells the main events of the parent story in the perspective of each member of the Super Peace Busters.
Summary taken from: MyAnimeList