Andy Lau plays Andy, an extremely compulsive mahjong player who is constantly chased by debt collectors. He lives with the strain of a mother who is aging and coping with Alzheimer's, and with a younger brother, Louis, who is academically gifted but luckless at mahjong and whose fortunes dip there too. Louis is portrayed by Louis Koo as Tin-lok, a character whose optimism clashes with his mounting financial troubles. Andy’s world is a tightrope walked between mounting pressure, dwindling resources, and a stubborn hope that luck will swing back in his favor.
One fateful day, Andy crosses paths with Gigi, Gigi Leung Wing-Kei, who begins as a thief but soon becomes a catalyst for his fortunes. Her presence brings Andy an extraordinary run of luck at the tables, turning him from desperate debtor into a man of remarkable wealth. The newfound wealth intensifies their bond, and for a time, Andy finds himself drawn to the idea of a future with Gigi.
Yet the relationship frays over a fundamental flaw in Gigi’s nature. She is a sore loser who throws temper tantrums at the slightest loss, and Andy cannot endure the volatility that accompanies every game. He proposes marriage only if she can play with grace and control, a test she cannot pass. Despite his love for her, Andy chooses not to marry, a decision that weighs heavily on both of them as life outside mahjong grows more complicated.
Meanwhile, the family saga deepens. Andy’s mother’s condition worsens, casting a somber shadow over the bungalow they share. Louis’s luck runs dry as bankruptcy looms, forcing him to move in with Andy. A devious mahjong player, Sean, drags Louis further into trouble, conning him of money and clothes. On the other side of the con game stand a pair of minor players, including Cherrie Ying Choi-Yi as a member of the team who grows to care for Louis. Sean’s operation tightens its grip, and the stakes in the underground world of mahjong escalate.
Gigi, disappointed by Andy’s refusal to marry, slips back into the wrong crowd—mahjong con men led by Sean. In a bid to shield Gigi from the trap she’s slipping toward, Andy makes one last, selfless stand: he challenges Sean to a high-stakes game to slow the con, and loses badly. The act is costly, and Gigi is moved by his sacrifice, returning to him with a vow to become a better person. Before she departs again, she offers him a blessing, a moment that rekindles Andy’s stubborn optimism.
Back on the home front, Louis unveils a mahjong computer game with his new partner, a development that leads to a sponsor’s invitation for a big tournament. The stage is set for Andy to enter the contest against Sean, Sean’s father, and a henchman in a final that tests more than just skill. Andy secures a seat in the final, and the showdown unfolds with the same calm, confident precision that once carried him to fortune. He wins the final round, but Sean, hungry for revenge, calls for a rematch. In a poignant turn, Andy chooses to relinquish the prize to Sean, proving a hard-won humility and the depth of his improbable redemption. Sean, recognizing the error of his ways, resolves to learn from Andy rather than defeat him.
With the competition behind him, Andy regains all his money and channels his experience into a new dream: a mahjong school by the sea where he can teach and mentor others. He also begins a life with Gigi, whose love and growth have transformed her as well. In the end, the luck that once defined him returns in a steady, enduring form, and Andy finds the balance he had long sought between passion and responsibility.
