[1] Despite no hype or big stars, the thriller gave a strong performance in the ratings, ending its run at 22.1% (number one in its timeslot).

Its rise in popularity was based on the tightly written and well-structured storyline, solid direction, and cast members' acting skills.

[2][3] The series tells the story of Detective Baek Hong-suk, a happily married family man whose life is shattered when his 15-year-old daughter is killed in a car accident, causing his wife to go into a state of shock, eventually killing herself and leaving Hong-suk a widower.

He later discovers his daughter's death was the result of a conspiracy led by politician Kang Dong-yoon, to secure his political future as a presidential candidate.

Hong-suk goes from loving, doting father and cop to harrowed man hellbent on revenge, as Kang continues to rise in power.