Horizon in the Middle of Nowhere

In a distant future, humanity flees a ruined Earth for the stars—only to be forced back by an unexplained phenomenon that makes space travel impossible. Earth proves unlivable everywhere but Japan, so vast pocket dimensions are built around it to house the population. Seeking a path back to space, people begin reenacting human history according to a sacred text known as the Testament, turning the reconstruction of the past into a guiding mandate.

By Testament Era 1413, the nations within those pocket dimensions invade Japan, carving it into feudal territories and driving out its original inhabitants. Centuries later in 1648, the displaced Japanese live aboard the city-ship Musashi, which continually circles Japan under the watch of the Testament Union, the organization overseeing the historical reenactment. When the Testament abruptly stops revealing what comes after 1648, talk of war and an impending apocalypse spreads—and Toori Aoi, leader of Musashi Ariadust Academy’s Supreme Federation and student council president, moves with his classmates to seize the moment and fight to reclaim their homeland.