As leader of a crime investigation team, Han Tae Joo has propelled his career and risen through the ranks by trusting data over all else. One day, while investigating a serial murder case, he has an accident. When he wakes up, he suddenly finds himself in the winter of 1988. He doesn't know why, but he's now a detective appointed to work at a police station in a small city. To getback to the present day, Han Tae Joo tries to solve the case.