Hundreds of cash-strapped players accept a strange invitation to compete in children's games. Inside, a tempting prize awaits with deadly high stakes. A survival game that has a whopping 45.6 billion-won prize at stake.

A high school student with amnesia tries to uncover what has happened to her. All leading her into deeper troubles ultimately revealing a darkness she could not have imagined.

Followed by Ma Seok-do, who heads to a foreign country to extradite a suspect. However, he discovers additional murder cases and learns about a killer who had committed crimes against tourists for many years.