In Shanghai during the Republic of China, prosperity and darkness intertwined, and countless unknown secrets were hidden behind the peaceful singing and dancing. Gu Mingyuan, a private detective who studied in England, returned to Shanghai because of a painful past and opened a detective agency in the French Concession. He is calm and wise, good at logical reasoning and psychological analysis.
One day, Su Wanqing, the most famous singer in Shanghai, died mysteriously during a performance at the Paramount Ballroom. An anonymous letter was left at the scene, suggesting that she held a secret that could shake Shanghai. With the assistance of his assistant Xiaomei, Gu Mingyuan traveled through the streets of Shanghai, from bustling dance halls to gloomy slums, from elegant western-style buildings to gangster underground casinos, and uncovered the truth of the case step by step. However, as the investigation progressed, Gu Mingyuan found that he was also involved in a larger conspiracy, and behind this conspiracy, there was hidden power enough to change the fate of Shanghai.
