Kaiji Ito is a 26-year-old man who leads a hand-to-mouth existence working half-heartedly at his part-time job at a convenience store. He sees no purpose in life and keeps putting things off, telling himself "one day" or "soon." Every now and then, he relieves his frustration by kicking expensive cars. Although he doesn’t admit it, he is the typical loser of today’s society.

One day, a mysterious, beautiful woman named Rinko Endo comes to see him. She is the president of an unscrupulous loan company and demands that Kaiji clear a debt he cosigned for a friend. With the company’s exorbitant interest rate, the amount is blown up to 2.02 million yen. Kaiji, who lives from hand to mouth, has no way of getting hold of such money. Then Endo sweetly informs the desperate Kaiji that he can not only clear the debt overnight but can also make a lot of money for himself at the same time. She says everything will become clear if he boards a ship that leaves Harumi Port in a few hours.

The ship’s name is Espoir, which means "hope" in French. Kaiji is skeptical at first but when Endo tells him that "it is his chance to change his life," he makes up his mind to accept the invitation, but without realizing he has taken Endo’s bait…And late that night, Kaiji boards the luxurious Espoir.

The cabin is permeated by a down-and-out aura from all the other passengers, losers like Kaiji who are deep in debt. "Winning is everything! If you lose, you’re trash! Staying alive without winning is out of the question!" Tonegawa (Teruyuki Kagawa), a high-ranking executive of the Teiai Group who oversees the ship, provokes the participants.

That night’s game is…Rock Scissors Paper! The players are given 12 cards and three star badges. The 12 cards consist of four cards each of the three hand gestures of rock, scissors, and paper. The rule is to play Rock Scissors Paper with the cards. The stars are bet as collateral. The players win if they lose all the cards and have at least three stars left at the end of the game. If not, they will be sent to the feared backroom, where they will be forced into hard labor that denies their dignity as human beings for the next few decades. The time limit is 30 minutes. The survival game of Restricted Rock Scissors Paper is about to begin.

But for Kaiji, this "ultimate game that could turn his life around" is merely a prelude. Soon, the players are caught up in the violent whirlwind of fate…