In 1986, the (fictional) city of Iltan in Gyeonggi Province: A young girl gets brutally murdered by an unknown person on a dark night. As the city is gripped by a succession of serial killings, a total of nine murders within a twelve-kilometer radius since 1993, the police conclude that a man they've nicknamed "Gap-dong" is behind the crimes. Detective Yang Cheol-gon is convinced that the actual killer is Ha Il-sik, a resident of the town who is intellectually challenged. His attempt to arrest the suspect fails as Ha commits suicide to prove his innocence. His death inspires his son Moo-yeom to become a police officer to clear his father's name and restore his honor.
Seventeen years later, Moo-yeom is a police detective who spends his career chasing dead ends and helping juvenile delinquents. After the statute of limitations on the case expires, Moo-yeom becomes resigned to the belief that Gap-dong is dead. But then a series of incidents occur in the town that bear an eerie resemblance to Gap-dong's crimes. Cheol-gon, now a well-decorated officer, has recently transferred back to Iltan, and to his dismay, Moo-yeom joins his investigation team to catch Gap-dong once and for all.
Cast
Main
Yoon Sang-hyun as Ha Moo-yeom, a detective in Iltan Police Department's violent crimes unit. He vows to avenge his wrongly accused father.[2]
Kim Min-jung as Maria Oh, a psychiatrist with a mysterious double life and a suspicious curiosity for all things Gap-dong.
Sung Dong-il as Yang Cheol-gon, a police inspector at the time of the original murders, and is now a well-decorated officer. Upon receiving his latest promotion, he surprises his superiors by requesting to be assigned back to Iltan, because he wants to end his career by capturing Gap-dong. Still convinced that Moo-yeom's father was the killer, he is extremely prejudiced against Moo-yeom, which makes for a combative working relationship. He also hiding grief of his daughter's death.
Kim Ji-won as Ma Ji-wool, a 17-year-old high school student and webtoon artist with the pen name "Matilda". Ji-wool becomes pivotal to the case when her webtoon titled The Beast's Path ends up foretelling the crimes. When she becomes the killer's next target, it also serves as a set of clues to find him.
Lee Joon as Ryu Tae-oh, an inmate of a prison psychiatric hospital, who becomes a barista after his release. With a genius IQ of 150, his excellent and detailed memory may prove valuable to cracking the case, but he also happens to have the disposition to be a dangerous psychopath, and considers Gap-dong his god and hero.[3][4][5][6]
Supporting
Jung In-gi as Cha Do-hyeok, the police section chief. He was in fact, the true culprit of the "Gap Dong" serial murders. He was sentenced to death nearing the end of the series
Jo Ji-hwan as Lee Hyung-nyeon, Moo-yeom's partner and wife
Ratings
In this table, the blue numbers represent the lowest ratings and the red numbers represent the highest ratings.
Ep.
Original broadcast date
Average audience share
AGB Nielsen
Nationwide
1
April 11, 2014
1.51%
2
April 12, 2014
1.98%
3
April 25, 2014
1.37%
4
April 26, 2014
1.64%
5
May 2, 2014
1.77%
6
May 3, 2014
1.76%
7
May 9, 2014
1.81%
8
May 10, 2014
2.32%
9
May 16, 2014
1.72%
10
May 17, 2014
2.00%
11
May 23, 2014
1.89%
12
May 24, 2014
2.08%
13
May 30, 2014
1.68%
14
May 31, 2014
1.91%
15
June 6, 2014
2.32%
16
June 7, 2014
2.23%
17
June 13, 2014
1.85%
18
June 14, 2014
2.17%
19
June 20, 2014
2.07%
20
June 21, 2014
2.13%
Average
1.91%
This drama airs on a cable channel/pay TV which normally has a relatively smaller audience compared to free-to-air TV/public broadcasters (KBS, SBS, MBC and EBS).
