Pao, a respected gang leader whose rep as a street fighter is one of the best. But Pao injures his head in a fight, which reduces his mental ability to that of a ten year-old. Rendered childlike, he has to count on best pal Biggie and girlfriend Yiu Yiu to get by. But with a big rumble looming, will Pao's childlike status spell doom for them all?

Brothers Lung and Fu were raised in Nam Tin housing project. Fu always thought joining the underworld is his only way out. Fu's girlfriend Yi is raped by local bully "Four Eyes" Keung. In a rage Lung and Fu attacked Four Eyes and injured him. They know they can't stay in Nam Tin and decide to move to Portland Street for a new life. Later in a gang fight, Fu insults Keung's boss, Crazy Fai and is chased by him and his gang...