Inferior gangster Flying Dragon (Chin Ka Lok) has a bad habit of gambling, he thus offends the three great gamble deceivers. Luckily his younger cousin, Roy (Jordon Chan), who comes back from America is extraordinarily lucky, he can win every round of the game and saves Flying Dragon. Flying Dragon hence brings Roy to Mahjong casino to earn money for him. Roy observes the rivalry between two Mahjong geniuses Hua San Yuan (Yuen Wah) and Ge He Qing (Eric Kot) by chance, he witnesses the fate of them - one turns to be insane and one becomes bankrupt, and decides not to snatch the reputation of "The King of Mahjong". Though Roy has no desire to seize the fame, his good luck elicits the worry of aggressive Mie Luo (Pang Jin Chi) who then plans to harm Roy...