In the early Republic of China era, around the 1920s and 1930s, Shanghai is a bustling coastal metropolis where East meets West and Chinese and foreigners live side by side. Beneath its glittering surface, undercurrents swirl. Ling Xiao and Shen Zhibai begin as “unofficial partners” who can’t stand each other and constantly test and use one another. Gradually, they become each other’s most trusted confidants and ideal partners. They complement each other perfectly: one handles the outside world, from action to dealing with people, while the other takes care of analysis and technology.