The leader of the “northern barbarians” Liu Ji-zhen raised the son of the Tang commander Yuichi Gong, giving him the name Liu Wu-di (“Without rivals”). He sends him against the Tans and orders him to challenge old Yuichi to a duel. But the former servant of Yuichi, Yu Wen-ching, first in short, and then directly informs the young brave man about his origin.

Tang dignitaries Xu Mao-gun and Fang Xuan-lin are thinking of whom to send against the "northern barbarians." The “imperial kinsman” Li Tao-zong, a glutton and a binge, begs the hike, but his candidacy is rejected. Call on old Yuichi. The dignitaries doubt whether he will defeat the young hero in a battle with lashes, but the old man is confident in his abilities.

Old Yuichi converges in a duel with his son. He pretends to be fleeing the battlefield, and then opens to his father in a secluded place. However, he refuses to go to serve the Tanamas - one must first make some feat.

Young Yuichi grabs his "named father" Liu and takes him to the Tang camp. And there they are going to judge old Yuichi as a traitor, because he released the barbarian commander. Xu Mao-gong does not believe the commander’s excuses, and only the guarantee of Fang Xuan-ling saves the old man. But then young Yuichi appears with the captive leader of the enemies, and everything becomes clear. Liu Ji-zhen only now, before the execution, understands what mistake he made by feeding the enemy’s son.