A fiercely competitive police officer and an idealistic prosecutor, former high school classmates, reunite while investigating a nationwide serial murder case, pulling them into both a dangerous pursuit and an unresolved personal past.

A drama about Cha Yeon-ho, a reasonable individualist from KAIST, and Min So-hee, a traffic investigation ace with cool judgment and warm sensitivity at the Traffic Crime Investigation (TCI).

A former special forces soldier delivers revenge for victims of injustice while working for a secret organization that fronts as a taxi company.