Han Tae Joo works for the Seoul Criminal Investigation Division; he has built his career by relying on scientific data more than anything else. He is too rigid when it comes to the rules, and one day, while investigating a serial murder case, he has an accident. He wakes up as a Deputy Inspector at a small police station in the winter of 1988. He doesn’t know why, but he finds himself having to deal with the police brutality of that era and realizes that he must do something in the past to be able to return to his own time.