Lee Jung-woo (Jung Woo-sung), the best agent of the South Korean Counter-Terrorism Bureau, encounters Yoon Hye-in (Soo Ae), the guide of the Intelligence Bureau exhibition hall, and is deeply attracted to her. However, he is repeatedly rejected by the iceberg beauty. He is puzzled and gradually feels that Hye-in seems to have a different life experience, forcing him to keep a distance from others. It is a critical moment for South Korea to independently develop the latest nuclear reactor, and this news is like a thunderbolt for the organization called "Athena". This secret organization has been controlling the global energy market. In order to maintain its dominance, it does not hesitate to launch terrorist attacks and even provoke wars. This time, South Korea has become a thorn in their eyes. To achieve their goal, the organization mobilized its core members, and Sun Hyuk (Cha Seung-won), the director of the East Asia Division of the US Intelligence Agency, took advantage of his position to stop South Korea's research and development process at all costs, and it is necessary to set off another bloody storm. Sun He pretended to be sent back to South Korea by the US Intelligence Agency to assist the South Korean side. He immediately began to collect the latest intelligence on the development of nuclear reactors in East Asia on a large scale, and even went on a killing spree to eliminate all members of the Athena organization who knew about it or were discovered by the South Korean Anti-Terrorism Bureau. The continuous bizarre cases aroused the suspicion of the Anti-Terrorism Bureau. By tracing clues, it was discovered that the accomplices of the murdered suspect were now plotting further in Vicenza, Italy. Li Zhengyu and his predecessor Jin Jixiu (played by Kim Min-jong) were sent to Vicenza to investigate the truth. Li Zhengyu, who had no clue at first, experienced waves of sneak attacks, and finally discovered that the other party's goal was to kidnap the only daughter of the South Korean president who was studying in Vicenza under an assumed name...