In 1941, various forces were entrenched in the Shanghai Concession during the isolation period. Gu Xingzhi, a code-breaking expert who is proficient in Japanese culture, was forced to be involved in the deadly game at Agent 76 headquarters due to an accident, walking on the edge of the knife as a double agent. His only partner is Shen Xiyue, a communications department actress with a cold appearance and a mysterious identity. In the crises of intelligence transmission, the two went from testing each other to trusting each other with their lives. They used origami codes to transmit top-secret information, tightly intertwining their personal destiny with the danger of their family and country. When trust and betrayal go hand in hand, every decision may prevent dawn from ever coming.
