In 1945, as the War of Resistance Against Japan neared its end, the struggle between the Nationalists, Communists, and Japanese grew increasingly fierce. Beneath the calm surface, undercurrents were surging. When Li Haifeng, a Juntong agent, defected to Wang Jingwei's collaborationist regime in Nanjing, Yu Zecheng (played by Sun Honglei), a member of Juntong's intelligence division, was ordered to go to Nanjing and assassinate the traitor. But unexpectedly, he embarked on a different path. Recruited by the Chinese Communist Party, Yu returned to Juntong as an underground agent, becoming a nail driven into the heart of the Kuomintang. To assist him, the Party organization sent Cui Ping (played by Yao Chen), a hot-tempered, outspoken young woman, to pose as Yu's wife. As time passed, the conflict between the Nationalists and Communists grew ever more intense.
