Zimoxi (Yuen Wah), a super gambler who is good at mahjong, poker and other gambling methods, hides from high-interest debts in a tea restaurant. He meets a waiter named Awang (Roger Kwok) who has a super memory. He suddenly has an idea to train him to be a mahjong master to help him win big money. He doesn't want to be severely taught a lesson by the boss's wife Shisan Fei (Yuen Qiu). However, Awang finally keeps Shisan Fei from Zimoxi and wanders around casinos of all sizes, helping Zimoxi make a lot of money. Awang meets the beautiful girl Xue'er (Fiona Fung) by chance, and then they develop true feelings, but Awang doesn't know that she is the mistress of the wealthy gangster boss Tin Kau (Wong Jing) in Macau. When he and Zimoxi visit Tin Kau, he is beaten into a brain-damaged state. Shisan Fei, who has always loved Awang, sees this and decides to return to the underworld. It turns out that she is the "Queen of Mahjong" who has retired from the underworld for many years.