Han Tae Joo 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 the winter of 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.