Beyond the Clouds, the Promised Place

In a Japan divided in two, Hiroki and Takuya, middle-school boys in Tsugaru, are quietly building an aircraft of their own, aiming for the Union's tower standing across the water. They promise to take their classmate Sayuri up to it, and that summer she disappears without telling them why. Three years later Hiroki finds her again, asleep and unable to wake, and learns what the tower has to do with her.