On what appears to be a typical evening, an elderly homeless man roams Seoul Station, bearing a bloody wound on his neck. Although his friend attempts to help, the man fails to get proper medical care and passes away. Yet, when the friend goes to report the body, the corpse has vanished without a trace. Chaos erupts shortly after, as it becomes clear the old man was the initial casualty of a violent zombie outbreak. With disorder spreading around Seoul Station, survivors from diverse walks of life are forced to struggle for survival.