Plot
Ko Chun is a world-famous gambler, so renowned and talented at winning various games of chance that he is referred to as the "God of Gamblers". He keeps his identity secret from the public (and avoids photographs so his face is not recognised), but is known for three characteristics: his slicked-back hairstyle, his love of Feodora brand chocolate, and his jade pinky ring.
Ko Chun arrives in Tokyo, accompanied by his girlfriend Janet and his assistant and cousin Ko Yee, for a match with Tanaka, the country's top ranked gambler. After convincingly defeating Tanaka in games of Mahjong and dice, Tanaka concedes defeat and asserts that Ko Chun "really [is] God".
Tanaka asks Chun to help him take revenge on Chan Kam-sing aka the "Demon of Gamblers", a famous Singaporean gambler who cheated Tanaka's father before driving him to suicide, by besting Chan in a high-stakes poker match. Ko Chun agrees, merely asking for a box of chocolate as payment. In gratitude, Tanaka sends his bodyguard, former Army of the Republic of Vietnam Special Forces Operative, Dragon, to accompany Ko Chun for protection. Chun wins the game, but Chan sends a duo of thugs in retribution. Chun fights them off with Dragon's help.
Meanwhile, Little Knife, an avid but mediocre gambler who idolises the God of Gamblers, sets a trap for an Indian neighbour as a practical joke. After a fight on a train between Ko Chun, Dragon, and henchmen sent by one of Ko Chun's rivals, Ko happens to accidentally stumble into Knife's trap. Ko falls down a hill, hitting his head, and subsequently suffers from amnesia and regresses to a childlike state.
Knife, not knowing who the unnamed stranger is, takes him in and names him "Chocolate" due to the man's seemingly obsessive love for the candy. Initially Knife is impatient with Chocolate's childish innocence and often yells at him, but soon recognises that "Chocolate" has innate gambling talent and begins to exploit his abilities in local poker games and gambling dens. As time passes, Knife comes to care for Chocolate and seeks to find a way to restore his memory.
Back at Ko Chun's mansion, it is revealed that Janet has been searching for Chun for ten days to no avail. Ko Yee, who is jealous of Chun's success and wealth, makes advances on her, which she rejects; finally, while attempting to rape her, Yee accidentally knocks Janet off the balcony, killing her. He discovers that she has been recording what has been transpiring and proceeds to burn the tape. Later, Yee allies himself with Chan Kam-sing and Ko Chun's other rival and they send assassins to find and kill Chun.
Eventually, the assassins find Chun, Knife, and their friends and attempt to kill them, but Dragon arrives to protect them after tracking Chun down. A fierce shootout ensues in a shopping centre, in which Knife saves Chun from an attempt on his life by Ko Yee. During the fight, Dragon is wounded, causing Chun to snap out of his child persona briefly to kill the rest of the assailants. However, after regressing back to his childlike state, Chun becomes horrified at the carnage and runs out into the street where he is struck by a vehicle.
Chun awakens in the hospital with his regular persona, but no memory of the events or people he met after the fight. He is informed by Ko Yee, who is feigning loyalty, that Janet had killed herself. Knife arrives and attempts to warn Chun of Ko Yee's treachery but Yee has Knife thrown out. Later, Ko Yee gives Chan Kam-sing special eyeglasses that will allow him to cheat during his upcoming poker match with Chun by reading invisible markings on the cards.
Chun, Yee, Tanaka and Dragon arrive on Chan Kam-sing's yacht for the climactic game of five-card stud. Knife, having sneaked onto the boat, again attempts to warn Chun of the danger he is in. Chun agrees to hear Knife out later but admonishes him not to interfere with the poker game.
With his ability to see the markings on the cards, Chan Kam-Sing dominates the first two rounds. After losing all of Tanaka's money, Ko Chun puts up his entire personal portfolio of wealth and holdings against Chan's wealth. Chan, using his glasses to see that Ko Chun has an inferior hand, agrees, showing his cards and gloating over his victory. Ko Chun, in turn, reveals that he actually has the superior hand and has won the game, having secretly altered the markings of the deck and using special contact lenses to read them.
Subsequently, Ko Chun tricks Chan Kam-sing into shooting Ko Yee. As Yee lies dying, Chun drops Janet's tape (which actually never finished burning) onto his body. Ko Chun then departs (as police arrive to take Chan into custody for murder) without speaking to Knife, much to the latter's dismay.
Ko Chun later surprises Knife at his home and reveals that he remembered Knife in the hospital and knew about Ko Yee's betrayal all along, but had to feign ignorance to execute his plan properly. He promises to make it up to Knife by taking him to Las Vegas as his gambling partner.
