Hai-wa is a young shepherd boy who spends his days surveying the mountains for an enemy attack during the war against Japan (1937-45). Having uncovered some vital information, Hai-wa's father, a spy, entrusts his son with the duty of delivering it to Comrade Cheng of the Eighth Route Army. Along the way to the Communist base, Hai-wa repeatedly encounters enemy forces who bully and abuse him. Yet he manages to escape and, with the Imperial Army in pursuit, completes his mission by delivering the letter. The resistance forces subsequently use the information to launch an attack on the Japanese and liberate the region.