Synopsis：In 1931, due to betrayal, the party's underground organization in Shanghai was destroyed, plunging the revolutionary struggle into a reign of terror marked by arrests and killings. Ma Tianmu, a young party member facing a crisis during the Northern Expedition, fled to France. Under the guidance of his superior Wu Zhongxin and with the cooperation of his comrades in the party group, he posed as a manager of a foreign company in the French Concession, navigating among various bureaucratic aristocrats, gangsters, and police. He ultimately accomplished an impossible mission, successfully protecting and relocating the party's secret document, the "Central Library." The Kuomintang spy organization disguised as "Fuxingshe" obtained crucial intelligence, rescued patriots from the enemy's gunpoint, retrieved the secret "Confession" document from the patrol room in the French Concession, eliminated the traitor Pei Ruhai, and thwarted the conspiracies of Japanese spies and Kuomintang agents. Amidst the arduous struggle, the members of the "Party Group," represented by Ma Tianmu, remained true to their original aspirations, fearless of sacrifice, demonstrating strategic wisdom and an indomitable spirit, making significant contributions to the party's revolutionary struggle.