In the late autumn of 1941, Shanghai was undercurrent. Chen Yanzhi, an "antique dealer" who returned from Paris, was actually charged with a secret mission in Chongqing. He returned to Hong Kong with a code book to take over the "Yangu Zhai" left by his father, but he was accidentally involved in the transfer of Japanese arsenal blueprints. In Yanguzhai, he met Su Qingyuan, who had been keeping the shop for seven years. The two communicated with each other in secret codes, testing each other and protecting each other. Faced with the pursuit of Agent No. 76, The sacrifice of comrades, and the unknown crisis hidden in the dark, Chen Yanzhi and Su Qingyuan were forced to walk on the edge of a knife, explore the truth in the fog of troubled times, and use faith and courage to carve a way out of the dark river of Shanghai.
