Tan Chun Huang, a Bak kut teh stall owner, often leaves the stall to his sister Huimin to meet his bookie friends, 4D King and 4D Liang. Huimin disapproves of his gambling habits and neglect toward the soup’s quality. Meanwhile, Lee Yong Shun loses his job, and his assistant Richard Huang’s proposal is rejected. Their coworkers approach them to buy Anita Mui’s 4D number as Huang can help to make 4D bets with an illegal bookie, frustrating Shun, who warns against gambling. Shun is then caught running a red light by a traffic camera and destroys it in a fit of anger.
At a hawker center, a Crazy monk performs a stunt revealing the number 3791 before being arrested for scamming people. Though Tan—who sidelined as an illegal bookie—dismisses it as a scam but took in bets for the number and never placed the bets. The number later wins both first and second prize on the next draw, resulting Tan to borrow $15,000 from loan sharks to pay out to those who betted with him.
At home, Richard’s wife criticizes his gambling, especially after a neighbor wins the lottery and upgrades their home while Richard gains nothing. Lee and his partner Evita argue over spending, particularly after Lee prepares to move his mother in. Huang introduces two Chinese friends to Lee, helping Lee to rent them a room to cover expenses. In return, Huang asked for numbers to bet on 4D and was rejected by Lee and instead Lee suggested to run a business together.
Together with Tan, Huang and Lee decided to sell mango desserts and obtained a loan from a bank to open a store. On the opening day, a police raid occurs and arrested Lee for vandalism (for destroying the traffic camera), Lee's tenants and lion dancers, who were illegal immigrants. In the process, a gas explosion ruins the stall. Evita broke up with Lee after the arrest and the business was destroyed with the explosion.
Back home, Huang sees a vandalized neighbor’s flat, victim of loan sharks. Later, Tan is warned by his bookie contacts about police crackdowns. They lend him an additional $25,000, bringing his debt to $40,000. During a police ambush, Tan is arrested after attacking an officer. He is sentenced to 30 months in jail but was granted bail to see his family before serving his sentence. Tan lied to his family that he is travelling to China for work instead.
In jail, Tan reunites with Lee and the fake monk where they guess a number from the fake monk's actions. Huang visits and is urged by Tan to bet on 7272, promising to split the winnings. Despite needing the money for medical bills, Huang gives in. Unable to bet with Singapore Pools, the state-owned lottery company, Huang turns to another bookie to place the bet.
The number wins first prize and Huang receives $400,000. Though he initially plans to share, Huang and his wife decide to lie to Lee and Tan that he had failed to place the bet and keep the winnings. While living a comfortable life, Huang grows close to Susan, a hairdresser. After hearing of a murder related to illicit 4D winnings, he panics and discovers his wife has gambled the money away. After Lee and Tan are released from prison, they confront Huang and demand their share. When Huang denies winning, they kidnap Susan to lure him out. Huang confesses his affair and goes to rescue her. At the hideout, he admits to winning and then losing the money, before waking from the entire sequence as a nightmare.
In reality, Huang visits Lee and Tan and tells them they did win, but the money is gone. Upon their release, they’re invited to an empty Bak kut teh restaurant. Huang reveals he invested the winnings to open a restaurant as co-founders and with Tan as the chef of the restaurant to help him quit gambling. Tan becomes a professional chef, and the trio successfully expands the business, opening their eighth outlet at Jurong Point.
