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. When several Communists sacrificed, Chen Qian was strongly shocked and gradually strengthened his communist belief. After that, he cooperated with the Communist underground organization and successfully smashed the conspiracy of the Japanese aggressors. After the defeat of the Japanese army, Chen Qian returned to Juntong as a secret Communist Party member, and worked hand in hand with the new Communist Party's "Flying Sky".