Background: The fictional coastal city "Zhongming City" is famous for its ancient clock tower and frequent sea fog. The city is divided into old and new districts: the old district retains colonial-era buildings, and the alleys are densely packed like a maze; the new district is a rapidly developing commercial district, with high-rise buildings intertwined with old houses, hiding the secrets of class divisions.
- Core event: When a huge sea fog that had not been seen in ten years enveloped the city, three related cases occurred, ultimately pointing to an unsolved case ten years ago.
