The central premise is genuinely wild: the only way to stop an apocalypse is to date the girl causing it. That hook alone separates it from every other harem anime, and the show knows exactly what it's doing with the absurdity. The spirit designs are sharp enough that you actually want to see them in the next arc instead of just cycling through character types. The fanservice drowns out the plot more often than not, which kills momentum for anyone looking for actual stakes.
Thirty years ago, an interdimensional catastrophe called a spacequake leveled part of the world and killed millions. Now they happen without warning, and nobody knows why. High schooler Shidou stumbles into ground zero of one such disaster and encounters a girl who shouldn't exist: a Spirit, a being from another dimension whose very presence tears reality apart. His sister Kotori, secretly commanding a resistance airship, brings him into the fold with a revelation: Shidou has an inexplicable ability to seal away a Spirit's destructive power. The method, however, is unconventional. He has to seduce them. Date them. Make them fall in love with him so completely that their power transfers to him and renders them harmless. What starts as an absurd last-ditch strategy becomes his life as more Spirits appear, each with their own reasons for being here and their own dangers to manage. Comedy and genuine romance collide with apocalyptic stakes as Shidou navigates dating superpowered girls while the world burns around him.