The protagonist, Lin Yu, is a son of a wealthy family who returned from studying abroad, with the ambition of serving the country. After witnessing the atrocities committed by the Japanese invaders and the chaos of the domestic situation, he resolutely devoted himself to espionage work and joined the underground party organization of the Communist Party of China. Relying on his intelligence, extraordinary courage and familiarity with the city, he gradually emerged in Shanghai's intelligence network.
During his mission, Lin Yu met Su Yao, a military agent who also worked hard for the anti-Japanese cause. From the initial mutual suspicion to the later cooperation, the two jointly fought against the Japanese intelligence agency "Mei Agency" and the spy organization No. 76 Of the Wang Puppet Government. However, as the war situation changed, potential conflicts between the Kuomintang and the Communist Party gradually surfaced, and the differences in beliefs and positions between Lin Yu and Su Yao also began to become highlighted.
At the same time, Japan dispatched the cunning spy leader Yamamoto Ichiro. His ruthless methods and meticulous thinking brought huge obstacles to the intelligence work of Lin Yu and others. In crisis after crisis, Lin Yu not only had to face the pursuit of the Japanese and Wang Puppet spies, but also had to guard against suspicion and frame-up from within the Kuomintang. But he always stuck to his faith, relied on his firm will and outstanding resourcefulness to resolve crises time and time again, delivered important information, and made indelible contributions to the victory of the Anti-Japanese War and the future development of the country. In the end, at the darkest moment before dawn, Lin Yu successfully completed a key task related to the fate of the country and ushered in the dawn of victory.
