In Shanghai in 1943, Chen Qian, a military agent, was ordered to assassinate the Japanese, but fell into the trap of Yujiro Ida, the head of Japan's plum agency. Born on the day, and accidentally learned of the Japanese conspiracy. In order to stop the sinister plan of the invaders, Chen Qian began to receive special training, disguised as a Japanese envoy to visit Mei's agency again. Chen Qian, who went deep into the enemy's camp, walked step by step in the dark, walking on thin ice, and with the help of the Communist Party member Chun Yang, he repeatedly avoided danger.