Shanghai in the early years of the Republic of China. The housewife Gou Jixiang suffered misfortune, and her husband passed away and was wronged herself. In order to find out the cause of her husband's death and repay her innocence, Jixiang became a female detective. Mao Ruyi is an auspicious partner, kind-hearted, but arrogant. In solving the case, they had many conflicts. As the cooperation deepened, they gradually reached a tacit understanding, and under the pressure of the inspector Frank, they solved many suspicious cases, which not only allowed the wicked to be punished, but also helped many poor people at the bottom. Jixiang has transformed from a self-defeating housewife into a confident and independent new woman, and Ruyi has also transformed from a confused son to a courageous and responsible detective.