Master Truong, the old fending master of the emperor, is nearing the end of his life and he has not yet found his successor. The country has to be prepared for war and the Emperor is furiously impatient. He gives Master Truong two weeks to find that replacement.
Master Truong goes to visit a famous General (Master Wing) who had disappeared to become a simple fisherman. He lives with his two son (Tin and Tan) and her daughter (Lan, with a disfigured face) on the shores of the Lake Ba Bê. Master Truong knows very well the legend of the lake but this time he will really understand its meaning.
Master Truong tells Master Wing he wants to test his two sons, as people had told him a lot about their quality. Disappointed by the results, he also tests Lan.