The story takes place in 1930s Shanghai, the "Paris of the East," a city where prosperity and turmoil exist side by side. Gu Yuan, a talented young man newly appointed as a detective, shoulders the responsibility of keeping Shanghai safe.
Che Suwei is a renowned female forensic doctor making a name for herself in the field. With her exceptional expertise and calm, rational mind, she becomes Gu Yuan's trusted partner in solving cases. She can always piece together the truth from the smallest clues on a body, giving Gu Yuan crucial direction for his investigations.
Kang Yichen, president of Shanghai's leading chamber of commerce, has extensive connections and considerable wealth in the city. He puts his resources at Gu Yuan's disposal, offering intelligence and assistance of all kinds. Whether tracking a suspect's movements or investigating the interests tangled up behind a case, Kang Yichen's unique advantages make him invaluable.
Li Simin, Gu Yuan's assistant, is gentle, adorable, quick-witted, and clever.
In this turbulent era, Gu Yuan joins forces with Che Suwei, Kang Yichen, and others. They face all manner of strange cases, from mysterious serial murders to complex commercial conspiracies. Each one is shrouded in fog and seems to offer no leads. Yet with their individual intelligence, courage, and expertise, they repeatedly venture into danger to uncover the truth. As they solve bizarre cases, they must not only match wits with cunning criminals, but also contend with the power struggles among Shanghai's factions and the dark corruption of officialdom. Still, they remain steadfast in their pursuit of justice, seeking light in the darkness and gradually exposing shocking secrets hidden behind Shanghai's glittering facade.