Principle-centered detective, Han Taejoo, gets into an accident while chasing after a suspected serial killer. When he wakes up after the accident, Taejoo finds himself in the year 1988.

18년 두뇌파 형사 VS 88년 육감파 형사 한태주(정경호)는 혼란스러운 와중에도 88년의 형사들과 함께 살인사건을 조사하지만, 과거 형사들의 수사 방식을 납득하지 못하고 강력반 강동철 계장(박성웅)과 대립하게 된다. 그리고 현재로 돌아가기 위해, 태주는 위험한 선택을 하는데.

Taejoo is confused and cannot determine whether everything is a dream or reality. He investigates a pickpocketing case with detectives from the Insung Seobu Police. However, his principle-centered investigation ends up putting the people around him in danger.

A strange incident is reported to the Insung Seobu police where signs of someone entering the house are found, but nothing was stolen. Taejoo becomes immersed in his old memories related to his family.

Taejoo encounters his father who passed away when he was a child. He reminisces about his childhood memories with his father. However, Taejoo confronts another murder case. As Taejoo approaches the case, the fragments of his memories that he wanted to forget or he had to forget gradually begin to come together.