Amid busy and indifferent passers-by, a rough-looking homeless man with a bleeding neck-wound finds refuge in bustling Seoul Station. Ignored by everyone, the weary vagabond, who seems to be bitten by something, slowly succumbs to his lethal trauma and dies, only to come back as a ravenous reanimated corpse, attacking and spreading his virulent disease. Now, against the backdrop of a sudden zombie outbreak, three lucky survivors--the teenager runaway, Hye-Sun; her layabout boyfriend, Ki-woong, and her desperate father, Suk-gyu--fight tooth-and-nail to reunite. But, this is only the first night of the unforeseen epidemic, and all hope seems lost. Are the walking dead the only monsters?