Months later, Kaiji meets Endo again, who kidnaps Kaiji and forces him into manual labor, constructing a nuclear fallout shelter for 15 years to pay his debt. After losing his saved up money, Kaiji joins the underground gambling circle.
Kaiji agrees to borrow 60,000 perica from foreman Otsuki to play cee-lo. The foreman explains the rules of the game. Kaiji starts playing with small bets, but later he bets 3,000 perica. He loses, but it fires him up to go all out to win.
After his initial loses, Kaiji keeps betting 3,000 multiple times during the night. Later he bets 5,000, and has a good win. However, Otsuki and his cohort Isawa Kaoru tricking him, making Kaiji fall further into debt hell.
Weeks later, Kaiji is in a group of 6 men called the Forty-fivers, who receive only half of their salaries. Kaiji figures out how Otsuki is cheating, and then convinces the Forty-fivers to pool their money to beat him.
Kaiji meets the son of Ishida, Hiromitsu, who blames his father for not bailing him out of dept. After three months, Kaiji and the Forty-fivers all return to full pay. On gambling night, Kaiji proposes no betting limit, and Otsuki accepts.
Kaiji and Otsuki prepare to face each other. For the first few matches, Kaiji does not bet over the old limit, but on a challenge from Otsuki who must deal twice, the Kaiji and Forty-fivers are going all-in, for a total of 507,000 perica.
When the foreman sees the large bet, he suspects that Kaiji has discovered how he is cheating with a special dice. Otsuki is forced to play with normal one, but then on the last throw he uses his special dice, and Kaiji grabs it.
Kaiji shows everyone that Otsuki is cheating, then tricks the foreman into betting again while they use their own special dice, making Otsuki lose 2,535,000 perica in total. When Otsuki was about to give up, Kaiji lands his finishing blow.
After Otsuki losing 18,252,000 perica, the team wants Kaiji to keep the money and twenty one-day outside pass to gamble for them. Outside, after teaming up with Sakazaki, Kaiji eyes The Bog, a pachinko machine with a ¥550 million jackpot.
Kaiji finds out that the Bog is rigged. Sakazaki is secretive about the details of his plan. He 'borrowes' ¥50 million from a company president's safe. On the appointed day, Sakazaki commences to play the Bog.
Sakazaki starts to play the Bog, using ¥10 million, and an another ¥10 million later. Kaiji overhears the security men talk of a device to prevent anyone winning. He warns Sakazaki's, but in his gambling frenzy he uses up all the money.
While Sakazaki continues losing, the casino manager, Ichijo Seiya, initiate the 'block' that stops the balls descending into the winning zone. Kaiji leaves with around ¥6 million. The next day, he gathers information about the casino.
Kaiji returns to Sakazaki's apartment, only to find it trashed and empty. Kaiji tracks Sakazaki down at a racetrack. He approaches Endo who is now broke but agrees to help. They end up agreeing to split the winnings three ways after costs.
Sakazaki plays the Bog again in disguise, then attacks and damages it. Ichijo realizes that it's a distraction, runs to his office to find Kaiji there. Days later, the Bog is repaired. On his final day on the surface, Kaiji makes his move.
Kaiji starts playing and more balls than expected drop between the pins and Ichijo is suspicious. He realize that Kaiji somehow entered the staff room and doctored the setting gauges. Panicking, Ichijo has the 'block' turned on.
Kaiji plays on even though it appears the chances of winning are zero. Meanwhile, Ichijo receives a request to send a live CCTV feed to the Teiai underground labor camp and to Hyodo. Kaiji continues to play, even after losing ¥20 million.
Kaiji continues to play until one ball makes it through to the plates below. The flipper rods bent because the replacements were modified by Kaiji. Ichijo is panicking, and receives a call from Hyodo telling him to let the game continue.
Kaiji has only ¥20 million left to try and beat the Bog. Slowly Ichijo comes to realize that Kaiji managed to not only tilt the machine to increase his odds of winning, but also create a favorable tilt on the casino building itself.
Kaiji's plan pays off, and he gets closer to winning with more balls dropping onto the third plate. Ichijo tilts the machine again in the same direction to prevent balls reaching the final plate as Kaiji uses his last ¥10 million.
Kaiji plays on, but he is on the verge of defeat, having lost all his money. He convinces Endo to lend him his last ¥10 million against his better judgment, but at an unreal interest rate. Kaiji returns to the machine for a final assault.
Kaiji commences to play, as the crowd watches, a number of balls circulating on the plates because the losing holes have become clogged with balls which are unable to exit the machine. This increases Kaiji's probability of winning.
Kaiji realizes too late that the lean they created possibly eliminating his chances of a ball dropping into the rear winning hole. Also, the clogged balls may soon drop out. He is now in a race against time before the money runs out.
Kaiji plays until the losing holes on even the third plate are blocked; however, Ichijo has the final weapon - air jets around the winning hole to deflect the balls. Kaiji is forced to play his remaining balls and pray for a miracle.
Kaiji has run out of money, but Sakazaki appears and gives Kaiji another ¥10 million 'borrowed' company money. As the plate overflowing with balls, some cascade down the winning hole. Hyodo sentences Ichijo to 1,050 years underground.
Kaiji's friends cash in ¥729 million. During a night of drinking, Endo drugs them, leaving Kaiji just over ¥61 million. On the day the Forty-fivers arrival, Kaiji is too ashamed to meet them but one of the men in black takes pity on him.