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

After being blinded in a coup against the king, Joseon's greatest swordsman goes into hiding, far removed from his city's anguish. But when traffickers kidnap his daughter, he has no choice but to unsheathe his sword once more.

Sun Woo comes from a poor family background. She was once a promising Taekwondo athlete, but she now works part-time jobs to support herself. One day, she is is selected to become the stand-in for Ji Yeon due to their similar appearance. Ji Yeon is the granddaughter of Beomhan Construction Company's chairman. She was the driver of a fatal hit-and-run car accident. Sun Woo must play Ji Yeon in front of the public and media. Meanwhile, Sun Woo becomes the target of Ho Joong’s hostility. Ho Joong is Ji Yeon’s stepbrother and he has an inferiority complex over Ji Yeon. He wants to become the successor to Beomhan Construction Company.

On March 26, 1991, five boys set off to the mountain to go frog hunting and never come back to their family. While a documentary producer, detective and professor try to solve the mystery of the incident, one of the boys' parents is a suspect.