In Shanghai in 1940, Ding Yi (played by Zhang Yishan) and Gu Yangshan (played by Han Dongjun) ) - one is a supporting actor of the Chaosheng Theater Troupe, living in the Shanghai Concession, making a living as a stand-in for the blind cryptographic expert Joseph Needham; the other is a military agent who returned from overseas, and accidentally kills Needham in order to prevent Needham from working for him. Ding Yi was involved in this accident, and Gu Yangshan fought side by side as an "assistant". With the help of Xian Biyun, the owner of the Chaosheng Theater Troupe, he lurked into the Japanese intelligence agency.
