Kumo no Mukou, Yakusoku no Basho

In an alternate post-World War II setting, Japan is divided, with the south aligned with the U.S. and the north, Hokkaido, controlled by the Union. A towering metallic structure rises from Hokkaido, visible from the northern end of Honshu. In 1996, three teenagers—Hiroki, Takuya, and Sayuri—vowed to construct a stealth aircraft to reach Hokkaido and investigate the tower. Their plan was interrupted when Sayuri fell into a coma and was sent to Tokyo for care. Three years later, their youthful idealism has faded, but their commitment to uncovering the tower's secrets remains. They seek the truth behind the tower and its connection to Sayuri's unexplained and closely monitored state.