In 1948, the struggle between the Kuomintang and the Communist Party had reached a white-hot stage. Although the general trend of the world has begun to emerge, it is also at a critical moment that is extremely dangerous and cannot afford any mistakes. One day in September, an underground member of the Communist Party of China was arrested in Shanghai and defected. In order to protect himself, he intended to give out an important undercover to Tan Zhongshu (played by Lin Yongjian), the director of the Eighth Bureau of the Central Intelligence of the Shanghai National Government at the time. This move is undoubtedly related to the success or failure of our party's revolution. Tan had previously had many encounters with our party's legendary agent Sailor. This time he was sure to win, but a series of changes made him realize the danger of the quagmire between the enemy and us. At the same time, in order to prevent the drugs in the hands of drug tycoon Zhuang Wenqing from falling into the hands of the People's Liberation Army, Tan implemented the Moses Plan through his son's school principal Duan Haiping (played by Lu Jianmin); Li Bohan, the ambitious director of the Eighth Bureau of Operations, pointed the spearhead at Liu Xinjie (played by Wu Xiubo), the director of the General Affairs Department who Tan trusted most, while frantically tracking down the Communist Party undercover. You come and I go, with open guns and hidden arrows, the most dangerous chess game before dawn is quietly laid out...