Lin Binghao (Han Shigui) is a major commander of the people's Army, when the situation on the Korean Peninsula was turbulent and wars continued. In order to get effective intelligence, Lin Binghao moved to South Korea, but the South Korean side was so suspicious of his identity that he was severely and ruthlessly tortured. It was so difficult that he finally became a staff member of the South Korean Security Department. He needs to train spies and analyze war intelligence from North Korea. During his tenure, he received a lot of indifference and suspicion, but he endured it in order to win the trust of the South Korean government. Finally he succeeded and began to provide effective information to North Korea. Soon he received a mission from the North Korean side, and he needed to give the important information he got to another North Korean spy Yoon Xiumi (played by Gao Xiaoying). Their task was successfully completed, but Lin Binghao's identity was immediately discovered by the South Korean side and the situation was very dangerous.