Ji-Sook (Hwang Su-Jeong) is sent to South Korea to take her husband Tae-Soo (Jang Hyun-Sung) back o North korea. Tae-Soo is an agent of the South Korea National Intelligence Service. 15 years ago, Tae-Soo infiltrated North Korea, marred Ji-Sook and had a son. He then returned to South Korea, leaving behind Ji-Sook and their son. Ji-Sook and her son were then sent to a forced labor camp due to her husband's actions. High-ranking North Korean officials trained Ji-Sook and sent her to South Korea to carry out a mission. Her mission is to persuade Tae-Soo to go back to North Korea. Ji-Sook's son is held as a hostage.