The plot is an old standard. China has been invaded and the rebels/resistance/loyalists want to throw them out and get the country back. Shih Szu is one of those rebels and Lo Lieh happens to be laying around when three guys decide to rape her. They hardly get further than just the thought when Lo pops up and playfully murders them. He expects gratitude from Shih Szu but she is not buying that pick up line. Lo then proceeds to stalk her, but in a nice movie hero sort of way, not creepy at all.
Lo began his career by playing heroes and is probably more remembered for his later villain roles. This role, a likeable rogue, seems a transition between the two extremes. He reminded me of Toshiro Mifune a bit.
Bolo spends a lot of time at the brothel. I am unsure of his actual job. This is one of Bolo's biggest roles and possibly my favorite. Initially Bolo gets whooped in a fight. That is usually the extent of his roles but not here. He starts as a bad guy (in that he is considered a Tartar but he was born a Song). There is a moment of character development and he joins the rebels.
The tunnel part was a waste of film and a totally dumb set. The wire work was about 20% too much and not needed. Otherwise the rest of the movie was typical Shaw Brothers above average quality.