Taking the "blue-purple ashes and mutilated corpse case" as a starting point, the series connects the "arson case at No. 37 Shen Lane" five years ago to reveal the truth behind the legend of "Twin Killers"——
? Superficial case: The murderer used ginkgo leaves + ashes to commit the crime, imitating the "funeral purification" ceremony, and targeted people who knew the secret of the arson case.
? Deep conspiracy: The arson case is actually a murder to cover up corruption. "Twin" is not the code name of the murderer, but the mirror image of the victim and the perpetrator.
Concept: Lin Shen said to Shen Yanzhou: "Bullets can't turn back, but memory can.