Chui Chik tries to lead a quiet life as a librarian. However, he is really a former test subject for a highly secretive supersoldier project and the instructor of a special commando unit dubbed “701.” The 701 squad is used for many government missions, but after one of the agents kills a team of policemen in an uncontrollable rage, the government decides to abort the project and eliminate all the subjects. Chui Chik helped the surviving 701 agents flee the extermination attempt. Having escaped, Chui Chik went separate ways from his team. Later, he discovers that the rest of the team were responsible for a violent crime spree that was beyond the capability of the local police. He sets out to stop them, donning a disguise and using the superhero alias of “Black Mask”. Having lost the ability to feel pain due to the surgery performed on the super-soldiers by the military, Black Mask is almost invulnerable.

So goes to the U.S. to open a martial arts school. Around this time, many Chinese people were sold off to U.S. railroad companies, and were brutally treated by the Americans under the harsh working conditions. Thus, the American workers’ hatred towards the Chinese immigrants is high. As a result, So gets into trouble with the Americans and the mob, and calls Master Wong for help.