In this animated film, Japan is under two regimes after the country's loss in World War II. Hokkaido remains under Japanese rule while America holds the rest, a bitter division that's wrenched the nation and left its citizens confused. Curious, Sayuri and her pals decide to build a vessel that would help them investigate a looming tower in Hokkaido, a plan they abandon when Sayuri falls ill. Is there a connection between her coma and the tower?