Four years after a zombie outbreak ravages the Korean peninsula, the region is devastated and deserted, quarantined from the rest of the world. Jung-seok, a former soldier who escaped the chaos, lives in Hong Kong, haunted by his past experiences and the family members he left behind. When he's given a chance to return to the peninsula on a covert mission to retrieve a truck full of cash, he seizes the opportunity, hoping for personal redemption. Teaming up with a small crew, Jung-seok navigates the treacherous, zombie-infested wasteland, driven by the promise of a substantial payday.

Upon arrival, however, the mission quickly goes awry, and Jung-seok's group encounters unexpected survivors: a group of locals who have adapted to the new world in various ways. Among these survivors are two young sisters, Joon and Yu-jin, and their mother, who reveal the depth of the tragedy and struggle experienced by those left behind. As they join forces, the group must contend with not only the relentless zombie hordes but also a militia of deranged survivors who pose an equally menacing threat. The survivors find themselves caught in a brutal battle for survival, weighed down by the guilt of their pasts and the overwhelming sense of loss that pervades the peninsula.