Ji-won is one of numerous North Korean undercover spies living in South Korea as ordinary citizens, until he's called to fulfill his mission: the assassination of Kim Jong-il's second cousin who wrote a book that the North Korean government deems as a great betrayal to the Fatherland. However, one of his fellow spies, Tae-soon, betrays his orders by switching his allegiance to South Korea, and Ji-won mistakenly becomes the target for both countries.