Synopsis：Set against the backdrop of the anti-Japanese war in Zhejiang in 1945, Han Wanning (codename "409," a Communist Party member), the daughter of a patriotic merchant, uses the pretense of finding a husband to resolve a family crisis, attracting Gu Yeting, a Kuomintang agent, to feign marriage into the family. The two go from adversaries to lovers, joining forces to fight against the Japanese invaders Yamamoto Jiro, the Wang Jingwei regime's agent Su Zhicheng, and the traitor Dai Bing (Gu Yeting's adoptive father, who colluded with the Japanese to kill her biological father). During missions such as rescuing a general's daughter, seizing medicine, and stealing a list of enemy agents, Gu Yeting gradually recognizes the corrupt nature of the Kuomintang and sides with the Communist Party. Ultimately, Dai Bing and Su Zhicheng perish together, and Yamamoto Jiro is annihilated. After the victory of the War of Resistance, Gu Yeting goes undercover on the front lines, while Han Wanning dedicates herself to reconstruction, and they agree to jointly build a school to welcome new students.