Ajie (Lau Dehua), a Mong Kok gangster in Kowloon, Hong Kong, works neatly, with great affection, and has the boss's demeanor. in order to take care of his impulsive and face-saving younger brother black fly (Zhang Xueyou), he is constantly dealing with all kinds of trouble. he even did not hesitate to make a feud between the black fly and the ruthless gangster (Wan Ziliang). Ah Jie's cousin A'e (Maggie Cheung) came to Mong Kok to see a doctor and stayed in his home temporarily, and the two slowly fell in love with each other, but because they were worried that their identity would eventually bring harm to A'e, Ah Jie chose to bury his mind. When Ajie understood that his true feelings could not help but want to resist fate, the black fly once again faced life danger because of good face, so a difficult problem of friendship and love that must be chosen was again placed in front of Ajie.