In Shanghai in 1941, Fang Jiashu, a Communist Party member lurking in No. 76 of the Wang Puppet Special Agent Headquarters, was in danger of being exposed. At this time, Tao Yuling, his adopted daughter-in-law and an underground worker of our party, broke into his life with her two children. In order to protect Fang Jiashu's hidden identity, she began to live with him as a family. On the other hand, Fang Jiashu also had the identity of a military agent and had to deal with various relationships. Even in such a complicated situation, Fang Jiashu still cleverly obtained more intelligence and benefits for our party.