- **Shadows of Old Cases**: Detective Gu Mingyuan was dismissed from the Scotland Yard case due to his misjudgment. He returned with an unhealed gunshot wound and was ostracized by the French Concession Police Department. This shame became the source of motivation for him to pursue the murderer.
- **The first signs of blood**: A photo of a mysterious girl was hidden in the incomplete pocket watch during the corpse dismemberment case in the paint factory. This pocket watch from the Japanese Consulate leads the case to a deeper conspiracy.
- **Undercurrent**: The special pinholes on the neck of the female corpse and the chemical burn marks on the residual limbs hint at human experiments with new poisons. As more mutilated corpses appear, the ghost of Japanese Unit 731 wanders around the concession.
- **Fog Tracking**: Gu Mingyuan teamed up with forensic doctor Su Wenyin to trace the turpentine smell left on the corpse to the secret room of the studio, and found that the victims were all mannequins. When they pieced together the girl's face on the canvas, they encountered a more horrifying truth...
