The final journey begins beyond the edge of survival.

Years after the fall of the Korean peninsula, the world has drawn a final boundary—The Last Line—a heavily fortified border designed to contain what remains of the outbreak. No one goes in. No one comes out. But when whispers emerge of a moving train deep within the quarantine zone… carrying survivors and a possible cure, everything changes.

Park Seo-joon leads a desperate international recovery team sent on a mission that was never meant to succeed. His objective is simple: locate the train, retrieve the girl, and get out alive. But nothing inside the quarantine zone follows logic anymore. The infected have evolved, faster and more unpredictable, reacting not just to movement—but to sound, to fear, to chaos itself. And the deeper they go, the more it becomes clear… the real danger may not be the infected at all.