Seong Gi-Hun (Lee Jung-Jae) gets fired from his job. His life is miserable. Seong Gi-Hun hears about a secret survival game, with a 45.6 billion won prize for the winner. He decides to take part in the game. Meanwhile, Cho Sang-Woo (Park Hae-Soo) is like a brother to Seong Gi-Hun and vice versa. They grew up in the same neighborhood. Despite his low-income family background, Cho Sang-Woo graduated from a prestigious university and found a good job. He now faces a crisis due to the misappropriation of company funds. He decides to take part in the secret survival game with Seong Gi-Hun. But in the end, only song Ji hun survives.