Due to mounting debt, Kaiji Itou is forced to revert to his previous way of life. One day, while going along the street, he comes into Yuuji Endou, who is looking for Kaiji because he owes money to the Teiai Group. Unaware of this, Kaiji joyfully follows Endou, expecting for another chance to bet, but quickly discovers the loan shark's true motives when he is abducted. Because Kaiji is unable to repay his massive debt, the Teiai Group sends him to work in an underground labor camp. He is told that he would have to spend the next 15 years in this purgatory, among other creditors, until he can earn his release. His sole chance of putting an early stop to this nightmare is by saving enough money to be able to go back to the surface for a single day.