Episode 1 of Doubt kicks off with Jang Tae-soo, a seasoned criminal profiler from the Yeongju police station, who is summoned to a crime scene. Detective Oh Jung-hwan reveals the grim discovery: the skeleton of a teenager unearthed by a villager. Interestingly, the villager was engaged in the illegal collection of honeydew when he stumbled upon the body.
Tae-soo, adhering to procedure, orders the villager to be taken into police custody. He informs Jung-hwan that he will conduct a thorough profile of the case once more evidence is gathered. Jung-hwan, however, becomes agitated, feeling that Tae-soo is not taking the investigation seriously. Later, Tae-soo returns home to prepare dinner for his daughter, Ha-bin. It’s revealed that Ha-bin, unbeknownst to Tae-soo, dropped out of school two months ago.
In a frantic search, Tae-soo tries to locate Ha-bin at various academies but to no avail. His calls to her go unanswered. Meanwhile, Ha-bin is on a train and witnesses two young girls stealing a passenger’s phone. Instead of intervening, she plays a siren sound on her phone, helping the girls escape. Ha-bin disembarks at the next station with the thieves in tow.
The situation escalates when Ha-bin and the girls are taken to the police station after a physical altercation. Tae-soo is called as Ha-bin’s guardian, learning that she was involved in phone thefts with the girls. When he finds out that she was staying at a motel with them, he immediately confronts her, asking what she was doing there.
On the ride home, the tension is palpable. Tae-soo suspects Ha-bin might be involved in the theft, but Ha-bin turns the tables, accusing him of being an absent father. She declares that she’s ready to live independently after her mother’s death, pointing out how Tae-soo’s divorce from her late mother emotionally abandoned her.
The following day, the skeleton case takes center stage at the police station. Section Chief Lee Seok-moon pulls Tae-soo aside to discuss his upcoming transfer. Tae-soo, eager to remain, asks if he can stay on the case, but Seok-moon dismisses the idea. Tae-soo is tasked with interviewing candidates to replace him. Among the candidates are Eo-jin, calm and collected, and Dae-hong, a more lighthearted and carefree applicant.
After the interviews, Tae-soo shares his thoughts with Seok-moon, wondering if he will be allowed to stay. Jung-hwan invites Tae-soo to dinner to commemorate his transfer, but Tae-soo declines. Later that night, Tae-soo notices Ha-bin walking home with a male friend. Suspicious, he confronts her and hears a phone vibrating inside her bag. The phone, however, belongs to her friend. Tae-soo confiscates it and asks Ha-bin to bring her friend over the next day to verify her story.
Tae-soo attempts to inspect the phone but finds it has been recently formatted. He asks a detective to trace the number. That night, Ha-bin receives a threatening message on her phone, heightening the mystery.
The next morning, Tae-soo is alarmed to find Ha-bin missing from her room. He tracks her down and, to his surprise, she is carrying a suitcase. Suspecting she’s trying to run away like the girls on the train, Tae-soo confronts her. Ha-bin reveals she is going on a school trip, and Tae-soo reluctantly drops her off at school, where other students also arrive with luggage.
At the station, Tae-soo is introduced to his replacements, Eo-jin and Dae-hong, who officially join the team. Eo-jin, however, is surprised to learn that Dae-hong has already secured the position, despite his easygoing demeanor. Meanwhile, Tae-soo’s mind is preoccupied with Ha-bin, but his calls to her go unanswered. He later receives video footage from the train, proving that Ha-bin wasn’t involved in the theft after all.
Tae-soo visits the room of his late wife, Ji-soo, and is haunted by a vision where Ji-soo accuses him of ruining Ha-bin’s life and indirectly causing her death. Stricken with guilt, Tae-soo wonders what he could have done differently.
The next morning, another case draws the attention of the detectives. A villager reports a pool of human blood found in a forest warehouse. The forensics team confirms the blood belongs to a woman with O+ blood type. Seok-moon instructs the team to locate the body, while Tae-soo requests to take the case as his final investigation before his transfer, to which Seok-moon agrees.
As Tae-soo evaluates the scene, he instructs Eo-jin and Dae-hong to conduct their own assessments. The investigation leads to the discovery of a small pit in the forest. Tae-soo holds a meeting with his team, where they discuss the logistics of the case. Back in the warehouse, Tae-soo theorizes that the culprit dismembered the body after killing the victim elsewhere and took steps to destroy evidence by burning it with an oil lamp.
Believing that the criminal understood investigative techniques, Tae-soo asserts that they must search for a second crime scene. Shortly after, a burned vehicle is found near the original crime scene, lending credence to Tae-soo’s theory. However, no conclusive evidence linking the vehicle to the victim is uncovered.
The tension mounts when Ha-bin’s teacher calls to report that Ha-bin is not on the school trip. In fact, she didn’t apply for it at all, prompting Tae-soo to worry. He frantically asks his colleague to locate Ha-bin. Simultaneously, he receives a call regarding the burned vehicle.
Tae-soo is horrified to discover that Ha-bin’s last known location was near the warehouse where the pool of blood was found. Fearing the worst, he rushes to the forensic lab to see if the DNA matches Ha-bin’s.
In a dramatic turn, the episode closes with Ha-bin attempting to take her life by running into traffic. Tae-soo receives a frantic call from the hospital, sending him rushing to her side.
Episode 2 of the psychological crime drama Doubt opens with a flashback to when Ha-bin was younger. Her mother, Ji-soo, hands divorce papers to Tae-soo, accusing him of being too focused on his job as a criminal profiler and suspecting their daughter, Ha-bin, of wrongdoing.
Returning to the present, Tae-soo finds Ha-bin in the hospital with a fractured hand following her attempted suicide. He takes her home, where she reveals that her grandmother will be staying with them for a few days. Despite a warm greeting to her grandmother, Ha-bin remains cold and distant toward Tae-soo.
Tae-soo rushes to the police station to join Detective Jung-hwan, who is leading the investigation into a mysterious warehouse murder case. New CCTV footage reveals a possible suspect—a teenager wearing a jacket identical to the one Ha-bin was wearing on the day of the incident. Tae-soo is visibly distracted as Jung-hwan discusses the unregistered car connected to the crime. When a list of phone numbers associated with the case is reviewed, Ha-bin’s number appears, raising more questions.
Tae-soo grows suspicious and searches Ha-bin’s room, discovering a bright red thread on a keychain that matches evidence found at the crime scene. He is about to confront her when a disturbing memory from the past surfaces—an event where he locked Ha-bin in a room and physically confronted her, believing she caused a serious accident. This traumatic incident led to Ji-soo filing for divorce.
Back in the present, Tae-soo joins Jung-hwan and his team as they examine new forensic evidence. The victim is identified as having diabetes. Surveillance footage from a car rental shop reveals one of the girls from the train theft case, Song Min-ah, renting the vehicle used in the crime. Tae-soo reviews her criminal history, finding multiple charges of fraud and theft. Despite his investigation, it is confirmed that Min-ah does not have diabetes.
Tae-soo continues his investigation by posing as an anonymous customer online, arranging to meet Min-ah at a motel. However, instead of Min-ah, her accomplice Ji-yeon arrives in a luxury car driven by a man named Young-min. Tae-soo notes the car’s license plate and follows Ji-yeon, but loses her when Young-min flees the scene.
At home, Tae-soo confronts Ha-bin about her involvement in the murder case. She admits to being on the mountain the night of the crime but claims her intention was to commit suicide. Meanwhile, Jung-hwan uncovers Min-ah’s identity but overlooks Ji-yeon’s involvement. Eo-jin informs Tae-soo that Min-ah was seen withdrawing cash from her bank account, leading the police to continue their search for her.
Young-min attempts to flee, but is caught and taken into custody by Jung-hwan. During the interrogation, he remains tight-lipped. Dae-hong discovers that Min-ah had two social media profiles, with one showing pictures of her bruised limbs. Tae-soo and Eo-jin visit a neighbor who lives near Min-ah’s house and suspect she may also be a victim of abuse.
At the same time, Ha-bin’s grandmother advises Tae-soo to trust his daughter rather than constantly doubting her. This adds to Tae-soo’s internal conflict as the investigation continues.
The police find out that Min-ah had checked into a motel, where Dae-hong discovers that Min-ah may have diabetes. This shocks Tae-soo, who realizes that the pool of blood found at the crime scene could be Min-ah’s, suggesting she is the victim.
Detective Kim arrests Ji-yeon, who was using Min-ah’s ATM card. During her interrogation, Ji-yeon threatens to expose Ha-bin’s connection to the case, revealing that Ha-bin was the last person to see Min-ah alive. Tae-soo is now forced to confront the possibility that Ha-bin could be directly involved in Min-ah’s disappearance and potential murder.
Then we get a flash back to a little Ha-bin is seen in the forest, covered in blood, with her younger brother missing. Later, his body is found at the base of a cliff, raising more questions about Ha-bin’s role in his death.
Tae-soo reflects on the tragic death of his son, recalling the cloth tied around his son’s eyes during a game of hide and seek with Ha-bin. He begins to wonder if Ha-bin might have been responsible for pushing her brother off the cliff.
Back home, Tae-soo notices the keychain, previously linked to the crime scene, is now missing from Ha-bin’s bag. When he directly confronts her, he asks if she killed Min-ah. The episode ends with Ha-bin responding by asking if her father believes her brother’s death was an accident or if Ji-soo’s death was a suicide, leaving viewers questioning the truth behind the family’s dark secrets.
The first two episodes of Doubt set a gripping foundation for this intense psychological thriller. Episode 1 introduces Tae-soo, a dedicated but troubled criminal profiler, and his strained relationship with his daughter Ha-bin, who quickly becomes entangled in a murder investigation. As suspicions around Ha-bin grow, Tae-soo’s past decisions and family trauma, including the death of his son and his divorce, weigh heavily on the unfolding mystery.
Episode 2 escalates the tension, blending Tae-soo’s personal turmoil with his professional responsibilities. As new evidence surfaces, the plot thickens, with the introduction of key suspects like Song Min-ah and Ji-yeon. The investigation takes unexpected turns, pushing Tae-soo to question Ha-bin’s involvement in multiple tragedies, including her brother’s death.
With its layered narrative and dark family secrets, Doubt draws viewers in with suspense and emotional depth, making it a must-watch for fans of crime dramas and psychological thrillers.