Seong Gi-hun, a divorced father and indebted gambler who lives with his elderly mother, is invited to play a series of children's games for a chance at a large cash prize. Accepting the offer, he is taken to an unknown location where he finds himself among 456 players who are all deeply in debt. The players are made to wear green tracksuits and are kept under watch at all times by masked guards in pink jumpsuits, with the games overseen by the Front Man, who wears a black mask and black uniform. The players soon discover that losing a game results in their death, with each death adding 100 million Won to the potential 45.6 billion Won grand prize. Gi-hun allies with other players, including his childhood friend Cho Sang-woo, to try to survive the physical and psychological twists of the games.