In a world suddenly overrun by monstrous beings born from human despair, the residents of a rundown apartment complex must fight for survival in this gripping Korean horror series. The story centers on Cha Hyun-soo, a reclusive teenager grappling with immense guilt and trauma, who discovers an inner strength when the apocalypse begins. Alongside a ragtag group of neighbors, including the mysterious but resilient Pyeon Sang-wook and the determined firefighter Seo Yi-kyung, Hyun-soo must navigate the terrifying new reality where humans can transform into monsters driven by their darkest desires. The series, starring Song Kang, Lee Jin-wook, and Lee Si-young, masterfully blends intense creature horror with deep psychological drama, exploring themes of guilt, redemption, and what it truly means to remain human in the face of overwhelming darkness. As the survivors barricade themselves inside their building, they soon realize the greatest threat may not be the monsters outside, but the secrets and betrayals festering within their own ranks.