Jiang Yan’s name is engraved on the back of a police badge, but he has never officially joined the force. When a serial killer deliberately recreates the police department’s methods, he is forced to team up with Su Ling, a mysterious woman from the archives. The old walkie-talkies sold by Chen Xiao, the parts repaired by Lin Ya, and the fake badges investigated by Huo Ran all point to a purge of undercover officers that was erased from the record. Meanwhile, in the shelter, a dog that can smell blood growls at Jiang Yan’s shadow, as if it remembers that the man who was supposed to have died never truly left.
