This show throws everything at you at once and somehow it works. The premise is genuinely insane, humanity reenacting history inside pocket dimensions to escape a dead Earth, but it commits to the logic so hard that you stop questioning and start following. The action pivots on philosophy instead of power scaling, the comedy lands because the characters refuse to take their own apocalypse seriously, and every episode adds a piece to a puzzle that keeps getting bigger. It's dense enough to demand your full attention, but rewarding enough that you'll rewatch scenes just to catch what you missed. By episode 13 you're not watching a show about history anymore; you're watching humans argue themselves toward survival.

Humanity's second chance at existence hinges on a strange historical reenactment. After abandoning a ruined Earth only to be mysteriously barred from space, humanity returns to find Japan the only habitable land. To find a way back to the stars, people start replaying human history as laid out in a holy book called the Testament. In the year 1413 of the Testament Era, the nations living in pocket dimensions around Japan invade, split the land into feudal fiefdoms and drive out its original people. By 1648, those refugees live aboard Musashi, a city ship that circles Japan under the watch of the Testament Union. When the Testament reveals nothing past 1648, talk of war and apocalypse spreads. Toori Aoi, student council president of Musashi Ariadust Academy, sees a chance and leads his classmates in a bid to win back their homeland. The story mixes action, comedy, drama and romance in a science fiction and fantasy setting.