The story takes place in Shanghai during the Republic of China. 

The well-known writer Xu Youyi (played by Zhang Nan) and the owner of a photo studio, Yan Wei (played by Sun Yihan), two women whose lives should have no intersection, got acquainted because of Xu Youyi's husband's betrayal and a serial murder case.
Xu Youyi, a well-known female writer in Shanghai, is beautiful and dignified and has a happy family. Little does she know that her husband has cheated on her manager, and her seemingly flashy family is crumbling in the torrent of the big era. On the other side, Yan Wei, a female killer disguised as the owner of a photo studio, is lonely, indifferent, and wandering around the city for the sky, looking for the only remaining temperature in the city. The two of them met, and then joined forces to eliminate the scumbag, eliminate the mistress, and save their lives. They are always suspicious of each other, but they always trust each other, and the only answer that fate gives them is to move forward and never back down