After Fang Zhimin, chairman of the Hong Tenth Army Corps’ Military and Political Committee, is killed, former propaganda officer Yang Weishan and company commander Pei Hanyue gather the surviving Red Army soldiers and form a guerrilla unit on Mopan Mountain. When the War of Resistance breaks out, Zhao Chuan, former director of the Red Army Political Department, is ordered to go up the mountain and relay the command for the guerrillas to come down and be reorganized. Yang Weishan mistakes him for a traitor and kills him. To get to the bottom of things, Pei Hanyue goes down the mountain to the New Fourth Army headquarters and learns that the reorganization was ordered by their superiors. Yang Weishan and Pei Hanyue agree to lead their troops down for reorganization, but they are attacked by the Kuomintang army. Pei Hanyue is gravely wounded, so Yang Weishan goes down the mountain himself to buy medicine and, along the way, shoots the Kuomintang chief of staff. Later, when the Kuomintang army launches a campaign to encircle and suppress Mopan Mountain, the guerrillas use the advantageous terrain of the Maze Valley to wipe them out. Yang Weishan then sends reconnaissance chief Chen Mingchao and a small squad down the mountain to establish an organization. They seize the Kuomintang army’s supply depot through a clever ruse. The guerrillas later join a battle to annihilate the Japanese invaders, but on their way back to the mountain, they are attacked by the Kuomintang army. Chen Mingchao and his squad die heroically. Back on the mountain, the guerrillas fall into dire straits, short of medicine and food. The Kuomintang army launches another campaign to encircle and suppress Mopan Mountain. Betrayed by a turncoat, the guerrillas suffer a devastating defeat. Yang Weishan leaps from a cliff to his death, while Pei Hanyue, wounded and betrayed, is captured and killed.
