A boy falls to his death at school, but Ok Chan-mi does not believe that her twin brother, Park Won-seok, committed suicide. Chan-mi transfers to her brother’s school, Yongtan High, and meets Ji Soo-heon, who witnessed her brother’s death. A “hero,” who avenges bullied students, appears at Yongtan High. Chan-mi speculates that it may be connected to her brother and starts looking for this hero.

Hundreds of cash-strapped players accept a strange invitation to compete in children’s games. Inside, a tempting prize awaits — with deadly high stakes.

Dreaming of changing the world, SEO Chang-dae takes part in KIM Woon-bum’s political campaign. To resist the current dictatorial ruling party, SEO adopts a very aggressive propaganda campaign, and it makes KIM become the strongest candidate in the opposition party. When ambitious SEO believes that unjustified means is necessary for politics, KIM has a firm belief that it is not real politics. While their conflict deepens, the ruling party secretly contacts SEO to win the next presidential election.