National Intelligence Service black ops agent, Chief Jo (Zo In-sung), while tracking an international crime in Southeast Asia, heads to Vladivostok following clues left by an informant who was sacrificed in his humint operation. There, Chief Jo contacts Chae Seon-hwa (Shin Se-kyung), a North Korean restaurant employee, and selects her as an informant for his new humint operation. Meanwhile, Park Geon (Park Jeong-min), a State Security Department chief dispatched to Vladivostok to investigate a disappearance case near the border, discovers that North Korean Consul General Hwang Chi-seong (Park Hae-joon) is involved behind the incident. People who collide in Vladivostok with different purposes. Deepening suspicions and uncertain truths, each of their choices leads them down an irreversible path…