In Shanghai in 1941, a spy stationed at No. 76, the secret service during Wang Jing Wei's puppet regime, is in danger of being exposed. At this time, a woman barges into his life with two children, and they must pretend to be a family to keep up a front.

Fang Jia Shu and Tao Yu Ling, a woman who was meant to be his wife since childhood, are both agents of the Communist underground. They have to try everything they can to ensure that all the members of their little family "perform well" in their roles in order to keep their identities safe. It proves to be no easy task given the suspicions from Li Li Xing, the head of No. 76 and intelligence director Ye Xing Cheng.

Fang Jia Shu also has another identity as a Juntong agent, which is complicated by fellow agent Su Ya Lu who is in love with him and team leader "Silver Fox" who is secretly monitoring his every move. Even in such a situation, Fang Jia Shu skilfully navigates different interests to complete his mission.