Lin Shujian, a criminal police trainee who just moved into an old house in the old city, was involved in the investigation of the "Red Umbrella Killer" after witnessing a series of murders. He unexpectedly discovered that there was a secret connection between the victim and the car accident he encountered before moving. Interpol Captain Zhou Yansong was ruthless and cynical on the surface, but he was extremely protective of her during the investigation. As the two worked together, Lin Shujian gradually realized that the murderer seemed to regard her as a "pseudo stand-in" for a certain past event, and all the clues ultimately pointed to Zhou Yansong's unsolved "disappearance of sister" case three years ago. When the black murderer's revenge plan comes to light, a life-and-death situation in the name of love is pushing the two of them to the critical point of evil and light.
