Officer Chan Ka Kui manages to put a major Hong Kong drug dealer behind the bars practically alone, after a shooting and an impressive chase inside a slum. Now, he must protect the boss' secretary, Selina, who will testify against the gangster in court.
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.
Hong Kong policewoman Yeung teams up with Taiwanese and Mainland officers to take down a gunrunning ring.
