S1 • E1
On a rainy evening, a murder case occurs in Saju-si, Gyeongsangnam-do. After 12 years, Jo Jung-Hyeon returns to her hometown with her family and falls into a panic when her niece Jo Jae-young, whom she loves more than anyone else, disappears. Meanwhile, detective Choi Hyung- in finds out that Cho Joo-ho, the true culprit of the chemical gas attack on Saju Station, which was recorded as the worst terrorist incident in history 12 years ago, was involved in the disappearance.
S1 • E2
Hyung-in Choi begins a full-scale investigation to find the missing Cho Jae-young. Hyeong-in Choi finds a tape, the clue to the incident, and discovers a terrifyingly bizarre sound in it. Meanwhile, Jo Jung-Hyeon, who is determined to find his nephew, Jo Jae-young, encounters strange patterns that he had forgotten in the places he was looking for clues. Jo Jung-Hyun senses that this pattern is related to the missing Jo Jae-young.
S1 • E3
Choi Hyung-in finds a clue of the disappearance of Jo Jae Young on a tape recorder with bizarre sounds, but when drugs are detected in a body found at the port, he notices the incident is involved with drug trafficking organizations. Jo Jung-Hyun discovers a VHS tape she had watched with her friends in the school district when she was in high school. A tape with creepy and bizarre content. However, Jung-Hyun and her friends at the school branch do not remember it.
S1 • E4
The search for Jo Jae-young has turned into a large-scale investigation. However, when fellow detective Si-jeong Lee is injured in an explosion, Hyung-in Choi is greatly frustrated. In the end, he withdraws from the case. At that time, Kim Hwan-Gyu, a leading suspect in the kidnapping of Jo Jae-young, surrenders. Jo Jung-Hyeon learns from Jo Jae-young's broadcast classmates that a month ago, Jo Jae-young had contacted them through an Internet messenger. Jo Jung-Hyun is convinced that Jae-young is still alive.
S1 • E5
The kidnapped Jo Jung-Hyeon barely wakes up in the main hall of Yeongjin-Kyo. Jo Jung-Hyeon, who is forced to perform an unknown ritual, notices that Jo Jae-young is here. However, a person called the Guru's agent informs Jo Jung-Hyeon of the shocking facts about the 1987 Saju Station terrorist incident. When Choi Hyeong-in learned that Jo Jae-young's disappearance was related to Yeongjin-Kyo, he continued the investigation alone. Hyung-in Choi realizes that Young Jin-Gyo has been watching him for a very long time and deeply.
S1 • E6
After being freed from kidnapping, Jo Jung-Hyeon sets out to find Jae-young again with Yong-tak, a friend of the school branch. Knowing that there is a clue to unravel the mystery entangled in the teaching papers they had made in the past, Jo Jung-Hyun accelerates. Meanwhile, the murder that seemed to have stopped taking place again in Saju. A series of bizarre murders that kill people around them and take their own lives. Hyung-in Choi decides to go his own way to get to the end of a long case.
S1 • E7
Hyung-in Choi hears from Jo Jung-hyeon about seeing Jae-young Jo in the parish of Yeongjin-gyo and the clues she has been looking for . With this, he went to the prison to pressure Jo Kyung-ho, but suffers a panic at a few words from Jo Kyung-ho. Meanwhile , Jo Jung-hyeon is caught by Im In-gwan, where he goes to find another clue and receives an unexpected offer. Jung-hyeon, who was in trouble, hears an unexpected voice from a tape delivered to his friends in the broadcasting club the day before Jae-young disappears.
S1 • E8
Jo Jung-hyeon rejects Lim In-gwan's offer, and as before, he and Yong-tak search for clues to find Jae-young. Meanwhile, Kim Hwan-gyu, who revealed that he tortured him, puts Choi Hyung-in in a difficult situation. While conducting an investigation alone with the help of the head of the yangban, Choi Hyung-in found out that an unidentified VHS tape called ' mix tape ' was spreading in the city of Saju. They exhibit unusual symptoms since the video " Tomorrow everything disappears ' is the word naebaetgo unknown, choehyeongin a hunch the valance crisis during four weeks are directed back to somewhere.
S1 • E9
Hyung-in Choi heads to the Cheonyang Water Purification Plant to prevent the imminent crisis in Saju-si. However, they are soon captured by the Youngjin Christians there. The four protagonists are bound choehyeongin Gas Chemical terrorism is not exactly what happened 12 years later, it will hear that there are plans for another attack. Four weeks later people are facing the water treatment plant attack and seem possessed by something, desperate efforts are made to prevent more accidents.
S1 • E10
A few days after the Cheonyang Water Purification Plant incident, Jo Kyung-ho disappears from the prison. As Jo Kyung-ho's escape leads to the sacrifice of people, Choi Hyeong-in hurries to find Jo Kyung-ho and finish everything. At the words of Jo Jung-hyeon who wanted to go find Jo Jo-ho together, Hyung-in Choi waits for her, but Jo Jung-hyun does not appear. And one address she left behind. Hyung-in Choi heads to the address left by Jo Jung-hyun, where he encounters an unexpected person.
S1 • E11
Jo Jung-Hyeon, who entered the Youngjin Bridge as the successor to replace Jae-young. Watching the faithful waiting for death there, she makes her own decisions. Jo Kyung-ho, who comes out of the prison, visits his mother Jeong Gyeong-Sook before reaching the end of the experiment, and Choi Hyung-in, who sets out to find the traces he left, finally realizes what Cho Gyeong-ho's message was for him.
S1 • E12
By sacrificing herself, Jung Hyun shows the believers that what the proxy is saying is wrong, and the Youngjingyo believers change their minds.
Jo Jung Hyun
Jo Jae Young [Kyung Ho's daughter]
Gyeong Joo
Moon Sook [Jae Young's best friend]
Jo Jung Hyun [Young]
PD Jung