Horizon in the Middle of Nowhere

Kyoukaisenjou no Horizon

In the far future, humans abandon a devastated Earth and traveled to outer space. However, due to unknown phenomenon that prevents them from traveling into space, humanity returns to Earth only to find it inhospitable except for Japan. To accomodate the entire human population, pocket dimensions are created around Japan to house in the populace. In order to find a way to retur...