The Liar Game tournament is revived by a mysterious new financier known only as Omega, not for financial gain, but to exact revenge on the previous champion, Shinichi Akiyama. The target is forced back into the game not by a direct challenge, but through the involvement of an innocent third party: Yu Shinomiya, a naive and honest university graduate.

Shinomiya receives the standard Liar Game package of 100 million yen along with an invitation to participate. Facing a massive penalty for refusing, she desperately turns to her psychology professor, the reluctant genius Akiyama, for help. He initially refuses, but a former player, Yuji Fukunaga, now working for the game, manipulates him into joining by preying on his sense of responsibility for Shinomiya. Akiyama enters the competition alongside Shinomiya and eighteen other contestants, all vying for a top prize of 2 billion yen.

The tournament is held at a secluded, high-tech facility, and the central game is a diabolical variant of musical chairs. The round begins with twenty players and fifteen numbered chairs. In each round, the surviving players elect a representative who must eliminate one of the remaining chairs. Each player receives twenty tokens, with each token a winner holds at the end being worth 100 million yen, while losers incur a debt of 200 million yen.

The players quickly fracture into warring factions. A charismatic religious cult leader, Takashi Harimoto, commands a loyal team of five. A ruthless and calculating player, Nobuteru Kiryu, forms his own alliance. Shinomiya, Akiyama, and a few former players, including the aggressive Mai Sakamaki, form a third group. The game becomes a complex battle of psychological manipulation, betrayal, and vote-trading as alliances form and dissolve. Shinomiya, struggling to trust Akiyama's opaque strategies, is manipulated by a spy within their own group and commits a critical act of betrayal. In a moment of desperation, she is goaded by Kiryu and eliminated for using violence, leaving Akiyama as the last member of his team.

As the game narrows to the final four players, Akiyama executes an intricate plan. He eliminates himself, seemingly handing victory to a minor player named Kenji Sarukawa. However, it is revealed that Akiyama had been secretly working to make every player’s tokens effectively worthless, forcing them to cooperate. In the end, the winners use their prize money to pay off the debts of the losers, resulting in no net gain or loss for anyone—a complete subversion of the game’s purpose. Omega’s revenge is thwarted, and Akiyama denies any altruistic motive, a lie that the observing Shinomiya sees through with a smile.