Despite being confused of his current situation, Tae Joo works hard with the detectives in 1988 to solve a murder case. Upon looking at the case, he is certain that it is a serial murder. He has a hard time accepting the way that the 1988 detectives work and gets into an argument with Dong Cheol. Tae Joo is determined to find his way back to 2018. In order to do so, he makes a dangerous decision.

A dead body turns up in a field of reeds. They find the suspect of the murder, but Tae Joo doesn't think that their suspect is the killer. Dong Cheol disagrees and is certain that the person they caught is the murderer. Meanwhile, Tae Joo begins to remember parts of his past that he had forgotten about.