It starts with the evil Japanese terrorizing the town. They challenge a kung fu master to an honorable fight presumably to make their dominance legitimate. They lose the fight and forget about honor and just kill him.
The son escapes and grows up learning martial arts along with our girl Shih Szu. The Japanese still terrorize the town and specifically seek a special kung fu manual. The other subplot is a love triangle between Chuan Yuan and two girls which the Japanese try to exploit.
I have been watching these films in chronological order and it has given me insight into their development. For example, the fight scenes changed with the addition of actors skilled in martial arts along with better ways of filming and editing the fight sequences.
The "training sequence" started its development in the early 1970s. Initially it was a few brief scenes simply to show the hero learning something new to validate that even though he lost before he could now beat the villain. By the early 1980s the training sequence evolved into a major story in itself. The actors used imaginative equipment that required extreme physical skills and everyone seemed to be trying to be more over the top in every movie. Some of these sequences became known as the best part of the whole movie. Since it was early in the development, the training sequence in this movie was brief. Three punches is brief as it gets!
Here we have another average martial arts movie from the 1970s. Shaw Brothers had a way of making these average movies look above average and they did exactly that here.