Horizon in the Middle of Nowhere

Horizon on the Middle of Nowhere (境界線上のホライゾン, Kyōkaisenjō no Horaizon, lit. "Horizon on the Borderline") is a Japanese light novel series written by Minoru Kawakami and illustrated by Satoyasu. The series is part of a six-stage (particularly the fourth one, called "Genesis") chronicle universe, with Minoru's other light novels (including Owari no Chronicle, the series pre-prequel) encompassing the other five. A 13-episode anime adaptation by Sunrise aired between October and December 2011. A 13-episode second season aired between July and September 2012. Both seasons have been licensed and released on DVD and Blu-ray by Sentai Filmworks in North America and Manga Entertainment in the UK. A video game adaptation for the PlayStation Portable titled Horizon in the Middle of Nowhere Portable (境界線上のホライゾン Portable, Kyōkaisen-jō no Horizon Portable) was developed by Tenky, and was released in Japan on April 25, 2013.

Plot
In the far future, humans abandon the devastated Earth and move to the upper world "Tenjo". But Tenjo and the law of causation collapse by a war and humans returns to the Earth, which has turns into an inhabitable planet except for Shinshu area. Shinshu is too small to accommodate all the humans, so they duplicate the area and create "Juso Sekai". In order to rebuild Tenjo and the law of causation, the returned humans start reproduction of history from B.C. 10,000. When the reproduction completes until A.D. 1413, a war breaks out in Shinshu and Juso Sekai falls onto the original world. The humans living in Juso Sekai lose their land and invade the original world. People in Shinshu surrender and is divided by the invaders from Juso Sekai. They try to resume the history reproduction from A.D.1457, but the update of history terminates in A.D.1648. A rumor of apocalypse begins to spread around the world.