It is a historic espionage action drama, set in Shanghai and Seoul in 1933 during Japanese colonial rule. The Korean government in exile gives one of its top undercover operatives, Agent Yem (LEE Jung-jae, New World), a mission: recruit three people to infiltrate occupied Seoul and assassinate the Japanese general along with a Korean collaborator. He selects steely-eyed female sniper Ahn (JUN Gianna, The Thieves), a brawler Big Gun (JO Jin-ung, A Hard Day), and an explosives expert (CHOI Deok-mun). But Agent Yem is actually a double-agent for the Japanese and he hires hitman Hawaii Pistol (HA Jung-woo, The Terror Live, The Chaser) to kill the assassins.