Inferiorgangster 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 Gragon hence brings Roy to Mahjong casino to earm money for him. Roy observes the rivalry between two Mahjong geniuses Hua San Yuan (Yuen Wah) and Ge He Qing (Eric Kok) 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 sieze the fame, his good luck elicits the worry of aggressive Mie Luo (Pang Jin Chi) who plans to ham Roy....

Roy is a professional conman. Simmi, his lover cannot forgive him for the seceit their relationship is built on. To takes his mind of Simmi, he agrees to teach Ditu (Ritesh Deshmuk) the rules of the games. Suddenly, Roy who pride himself on being able to cheat anyone is pushed into a corner from where there is no exit and he is now left with on alternative but to take them all off, reveal his real self.