It begins when Yueh Hua assassinates the corrupt official. Lo Lieh is unable to capture him. Now his life is on the line if he cannot bring him back alive in four days.
I have written before that almost all martial arts movies can be sorted into four different plots. First is revenge as in "You killed my master. Prepare to die." Second is the martial arts expert has made a promise not to use his skills but eventually reaches the point where he must break that promise. Third is finding the right master or learning the right martial arts style or one particular technique to overcome the enemy's one weakness. Fourth is the tournament plot where martial artists gather for one big showdown. I find it amazing that Bruce Lee made four movies and each movie uses one of these four plots. There are a few more plots and this movie has my favorite.
I call this plot "The Iron Monkey". The main point is there is no protagonist and no antagonist, no good guy and no bad guy. In this movie both Yueh Hua and Lo Lieh are good guys. This was the same situation in the Donnie Yen's 1993 "Iron Monkey". (Also, here Li Ching is held prisoner and there Huang Fei Hung was imprisoned.)
When you have two good guys the climax and resolution of the story has to have two winners. In this movie the writing was a bit lazy by having Lo Lieh simply quit his job and allow Yueh Hua to remain free. "Iron Monkey" got it exactly right by using "the enemy of my enemy is my friend" and making the corrupt official the antagonist.
I have watched this movie twice already and it is on my list to watch again whenever the time seems appropriate. I recommend it to anyone, even if you are not a fan of this genre.