The premise pins you down immediately: a vertical maze of skyscrapers where the only rule is that masked killers own the space and you don't. Yuri survives not because she's special, but because she refuses to stop moving, and the show respects that desperation without asking you to root for redemption. The pacing collapses hard in the second half, turning precision into chaos, but those early episodes create a specific kind of dread, trapped in someone else's architecture with no exit strategy, that most survival shows never touch.

High schooler Yuri Honjou, 16, sees a masked figure split a man's head with an axe and runs, only to find herself shut inside a building where every door is locked. From the roof she sees a lifeless world of skyscrapers joined by suspension bridges, where masked killers cut down anyone they catch. Learning that her brother is trapped there too, Yuri resolves to find him, survive by fighting the masked figures, and bring down this senseless world. An action horror mystery adapted from a manga.