Jin-seok, a young man, moves to a new house with his mother, father, and older brother Yoo-seok. Things seem off to Jin-seok in their new home. One rainy night, he witnesses the abduction of Yoo-seok, being dragged into a car. Nineteen days pass and suddenly, Yoo-seok returns. Jin starts to notice discrepancies in his family's personality. He then realizes that they are not his family at all but people pretending to be his family. He escapes the house and goes to the police. When he tells them he is 21 years old, the officers, skeptical, ask him what year it is. He replies that it's 1997; the officer reveals that it is 2017. Jin is, in fact, 41 years old. A shocked Jin looks around and sees signs of modern life: a tablet, a smartphone; an LED flat-screen TV showing the current South Korean PresidentMoon Jae-in and United States President Donald Trump. He leaves confused, but is captured by the same "family" that was holding him captive. The young man pretending to be his brother, "Yoo-seok," tells Jin that twenty years ago, a little girl and her mother were murdered. The case went cold so the family of the victims hired "Yoo-seok" to find their murderer, who is Jin. In flashbacks, it is shown that Jin was abducted and tortured to confess, but maintained his innocence. A psychiatrist suggested that he had repressed his memory because the event was too traumatic. The team had the psychiatrist hypnotize him back to his last happy memory in 1997, figuring that if they can re-enact the events of the murder, Jin might be able to recover his memories and tell them what happened. Everything was going as planned until the night when Jin thought he saw Yoo-seok being abducted; he was actually arrested for fraud, and was gone for 19 days because that was how long he was in jail. Presently, Jin escapes the van and the young man crashes, while Jin accidentally gets hit by a stranger's car. He then regains his memories from 1997. In 1997, the opening scene from the film is shown, except this time, Jin is with his real parents and older brother, the real Yoo-seok. They get into a car accident that kills his parents. His brother is in critical condition and he desperately needs money for Yoo-seok's surgery but times are hard because of the 1997 Asian Financial Crisis. Jin goes online seeking a job, and is messaged by an anonymous person, telling Jin he'll pay him to kill someone's wife, but leave the two children unharmed. Jin's conscience doesn't allow him to go through with it. He is about to leave the house but the mother sees him, then the young daughter, who starts screaming, and Jin ends up killing them both. The youngest child, a little boy, comes out, and Jin tells him to go to bed. As he leaves, he discovers that this is actually the family of his brother's doctor. Jin meets with the anonymous man, who is indeed Yoo-seok's doctor, demanding to know why the doctor would have his own family killed. The doctor explains that it was to keep his children from becoming homeless due to the financial crisis; he had taken out multiple insurance policies on his wife. Since Jin not only killed his wife but also his daughter, the doctor says Yoo-seok will die as well. A struggle ensues and the doctor is accidentally pushed to his death. In the present, Jin wakes up in a hospital. The young man survived the crash and is about to kill Jin with a poisonous needle but Jin reveals that his memory has returned. The young man reveals that he was the little boy in the house twenty years ago when Jin killed his mother and sister. After the deaths of his parents and sister, his relatives took all the money and left him to grow up in an orphanage. He begs Jin to tell him why Jin didn't kill him too and whether the murders were planned by his father. A distraught Jin takes the entire blame but the young man doesn't believe him. Jin, now knowing he did in fact commit the murders, commits suicide in his hospital room with the poisonous needle; simultaneously, the young man comes to terms with the murder of his family, and also commits suicide by jumping out of the hospital window. The film flashes back to 1997. Jin's family is at the lake. Jin is stopped by a little boy offering him a lollipop. After he kindly declines, the little boy runs to his family. It is shown that it was the doctor's family, revealing why Jin did not kill the little boy.
began on March 11, 2017 and ended on June 8, 2017. For the film's premise, Jang Hang-jun took inspiration from a story told to him by a friend, who recalled how his cousin left home for about a month and seemed liked a radically different person when he returned. Jang also drew inspiration from french folktale Bluebeard.
