Han Tae-Joo (Jung Kyoung-Ho) leads a crime investigation team.
He has experienced a rapid rise in his career and he trusts data over people.
While investigating a serial murder case, he has an accident. When Han Tae-Joo wakes up, he finds himself in 1988.
He does not know why, but he is now a detective appointed to work at a police station in a small city.
To get back to the present day, Han Tae-Joo tries to solve a serial murder case.