After a tragic accident shatters Cha Hyun's family, the introverted high schooler swaps his gaming sanctuary for a solitary apartment life. But as eerie transformations grip those around him, including himself, and a haunting voice echoes in his mind, Hyun faces a nightmarish apocalypse. Struggling to stave off monstrous changes, Hyun bands with his neighbors to unearth the source of the epidemic and cling to their fading humanity in a bleak reality.