Dong-hyun is a high school student. One day, he falls from the rooftop and bumps into Pan-soo who is a passerby. Pan-soo is a member of a criminal organization. When the two men wake up in the hospital, they discover that they have switched bodies.
When his brother vanishes, ex-footballer and MMA star Ik-ho receives a call from a game planner who has turned the whole city into a board game that Ik-ho must navigate if he is to save his brother.
Follows Pete, a professional hitman, as he faces a group of assassins after the boss of a crime syndicate suspects disloyalty due to his attendance at Workaholics Anonymous meetings.