After a failed business venture, the debt-ridden chauffeur Seong Gi Hun lives his life gambling away the money he mooches off his elderly mother while failing to provide for her and his estranged daughter. When his life finally hits rock bottom, he receives an irresistible offer promising him a ₩45.6 billion prize in exchange for winning traditional Korean children's games against 455 other players, among them his childhood friend Cho Sang Woo. Commencing the games, the participants soon learn of the deadly consequences that come with losing.