Train engineer Ko In Ho finds his retreat back north blocked. He operates a military train behind the enemy lines of the Yankee imperialists and their South Korean puppet allies. He pretends to be a collaborator and is hated by his comrades. But he secretly establishes contact with the communist underground organizations so that he can smuggle his train and war supplies back to friendly territory. The Americans, fortified with alcohol, massacre civilians and hunt for enemies in their intense resolve to defeat communism and divide Korea.