Three kids make a promise under a tower that divides their country, then life pulls them apart in ways they never expected. Makoto Shinkai animates the exact feeling of watching something beautiful slip through your fingers, frame by frame. The tower stays visible in the distance the whole time, a permanent reminder that some promises break not because people stop caring, but because the world is bigger than what nine-year-olds can control.

Three teenagers in a Japan split in two after the war share a dream: build a plane and uncover the mystery of the enormous tower rising across the Tsugaru Strait. Hiroki and Takuya piece together an aircraft from a downed drone, and when their classmate Sayuri joins them, the three promise to fly to the tower together one summer. Then Sayuri develops a strange sleeping sickness and moves to Tokyo for treatment, and the project is abandoned. Three years later, Hiroki discovers she has been in a coma ever since and asks Takuya to help him find a way to wake her. Neither of them yet realizes that her condition is somehow tied to the tower and to the secrets of their world. A quiet science fiction romance and drama set against an alternate history.