Police profiler Park Hae Young (Lee Je Hoon) stares in terrified disbelief at the inexplicable change in his whiteboard list of victims of the Gyeonggi Nambu murder case. The eighth victim, Lee Mi Sun, has now shifted to having survived the attack. When his colleague, Jung Hun Gi (Lee Yoo Joon) wanders into the office, a shaking Hae Young asks if he changed the whiteboard. Hun Gi doesn’t even notice that there has been a change.
Hae Young runs out of the office, and from his car calls detective, Cha Soo Hyun (Kim Hye Soo). She also has no idea that something has changed, and believes that the eighth victim, Lee Mi Sun had survived the attack all along.
Back in 1989, police officer, Lee Jae Han (Jo Jin Woong) finds Lee Mi Sun, tied up by the train tracks, alive, but before he can help her, he’s attacked by a man in a black jacket and cap. Jae Han manages to dodge the attack and give chase when the culprit runs away, and finally appears to catch him by the side of the road, just as a bus drives away.
In the present, Hae Young goes to see one of the investigating detectives in the case, and asks him about Lee Mi Sun, the survivor. Rather than answer, the detective blames Jae Han for ruining everything. Hae Young is taken aback to hear Jae Han’s name, especially when the detective adds that Jae Han was babbling about some radio transmission.
In the past, Jae Han delivers Choi Young Shin, the man he believes to be the culprit, to the police station. The 1989 version of the same detective that Hae Young is speaking to takes custody of Choi Young Shin, whose repeated protestations of innocence fall on deaf ears.
In the present, Hae Young goes back to his own office, and begins to piece together the facts, that the Lee Jae Han that he’s been trading radio transmissions with is in the past, in 1989. Just then, exactly at 11:23pm, Hae Young’s radio goes off, with a call from the Jae Han of 1989. Jae Han is pleased with himself for catching Choi Young Shin, the man he believes to be the culprit, but Hae Young still can’t bring himself to believe that he’s speaking to someone in the past. Hae Young tells Jae Han that Choi Young Shin will die of a seizure in custody, while the real culprit kills another victim in front of the Ohsung-dong supermarket. Before Jae Han can ask what he’s talking about, the radio switches off.
Hae Young settles in front of the whiteboard to see if anything changes, while Jae Han runs back into the police station to find that Choi Young Shin has had a seizure and the detective in charge is frantically giving him CPR. Meanwhile, another victim is found in front of the Ohsung-dong market.
In the present, Hae Young goes through old newspaper files and finds a picture of Jae Han in the articles from the time. Finally convinced that the transmissions were real, Hae Young pulls out Jae Han’s personnel file. When Hae Young goes to find Soo Hyun, she’s at the home of the family of Lee Mi Sun, asking her widower if she can look at her belongings to see if there’s a clue. Believing that it was the constant police attention that led to Lee Mi Sun’s death, the widower ends the conversation by throwing water in Soo Hyun’s face. An apologetic Soo Hyun can do nothing but leave. Outside, Soo Hyun ignores Hae Young’s offer of a handkerchief, but as they walk away, they’re chased down by Lee Mi Sun’s daughter.
In a coffee shop, the daughter confesses that her mother never spoke to them about the incident, but she still has some of her mother’s belongings to show them. She tells them that her mother was always grateful to the policeman that saved her, since she was pregnant at the time, and neither she nor her daughter would be alive if not for his timely intervention.
As the daughter leaves, Soo Hyun asks Hae Young why he’s visiting the families of the victims rather than doing the work she assigned him. Hae Young tries to ask Soo Hyun what she would do if she could communicate with the past, but Soo Hyun thinks he’s making excuses. As Hae Young gives up and walks away, Soo Hyun gives in and tells him that she would try to protect the person that was important to her, even if it resulted in disaster.
Later in the office, Soo Hyun thinks back to the last time she saw Jae Han, while at home, Hae Young resolves to try and save the last two victims. He compares the circumstances of the two remaining victims from before his intervention, and after, and figures out that even though the victims remained the same, the times of their murders had moved up, and their locations had changed to more populated areas. Hae Young realizes that, since he’s the only one that knows about the change, he’ll have to be the one to figure out who the killer is and stop the murders.
Back in 1989, the detectives from the Gyeonggi Nambu murder case question Jae Han about where he lost the culprit, but he has no answers. Angry about the fact that their colleague will likely go to jail for the death of Choi Young Shin, they tell him to turn in his badge. Jae Han asks about Lieutenant Park Hae Young again, but they no longer want to listen to him, so he hands in his badge and radio and leaves.
Jae Han goes to another police station, looking for Park Hae Young, and attacks the first person he sees, only to discover that he has the wrong person, and the Park Hae Young at this station is a woman. Realizing he’s made a mistake, Jae Han runs for it, straight to the workplace of the woman he likes. Jae Han is apparently suffering from terminal shyness, because when she notices him and says hi, he almost runs for it. It’s only through her intervention that he stops and gives her a Taser (so romantic!), tells her how it works and then runs away. Jae Han vows to catch the culprit, get a promotion and ask her out, while watching her nervously from a nearby fence.
In the present, Soo Hyun has put together the one thing that all the women had in common, which is that they took the same bus, Bus 95. The other members of the team, Hun Gi, and detective, Gye Chul (Kim Won Hae) are dismissive, but Hae Young gets excited and starts mapping out the locations of the attacks.
In 1989, Jae Han starts retracing his steps of the night he saved Lee Mi Sun, following the path where he chased the culprit, to the bus stop where he lost him. Jae Han comes to the conclusion that the culprit escaped on the bus.
Back in the present, Hae Young has already come to the same conclusion, but he takes it one step further. Following the attack of Lee Mi Sun, the culprit changed his pattern, and killed the next two women in rapid succession. Hae Young theorizes that he killed those women not because he was a serial killer, but because they had seen his face on the bus (one of the women on the bus is the woman that Jae Han has a crush on… uh oh). Surprised, Gye Chul wonders if Hae Young had talked to the detective in charge of the case, because that detective told Gye Chul that Jae Han had the exact same theory in 1989.
In 1989, Jae Han tries to convince the lead detective that the bus is the key to the case. The lead detective is skeptical, but another detective convinces him to at least ask the bus driver. At the police station, both the bus driver and one of the victim’s colleagues are being questioned when Jae Han butts in. The bus driver doesn’t remember anyone getting on the bus at that stop but the colleague looks surprised at the driver’s answer. The detective points out that if Jae Han’s theory is correct, then the bus driver would be the first to die, since he’d get the best look at the culprit’s face. Jae Han is befuddled by this turn of events, while in the present, both Soo Hyun and Hae Young are taken aback to have this theory destroyed so neatly. They ask about the bus driver, but Gye Chul had interviewed him and he’d confirmed his story. Soo Hyun asks about the colleague next, but Gye Chul hadn’t managed to get in touch with her. Soo Hyun gets her address from Gye Chul, and she and Hae Young go to talk to her.
In the car on the way there, Hae Young wonders why the culprit stopped killing, given that he must have become addicted to it. He lists all the theories as to what happened to the killer, but in the end, he wonders if the culprit is still among them? As if to answer that question, as they drive up to the victim’s colleague’s house, a man in a black hoodie walks away from it. They get no answer when they knock on the door, and when Soo Hyun looks in the window, she sees seeds scattered on the ground and the tv still on. Ignoring Hae Young’s protests, Soo Hyun pushes the door and walks in. Inside, they find the woman dead, tied up in the same way that the Gyeonggi Nambu victims were tied. Hae Young is convinced that it’s the same killer, but Soo Hyun says nothing.
Back at the police station, their section chief, Ahn Chi Soo (Jung Hae Kyun) asks Soo Hyun if it’s the Gyeonggi Nambu killer, but Soo Hyun can’t yet confirm. Chi Soo orders her to drop the investigation since the Gyeonggi police have jurisdiction. Soo Hyun protests, but he overrides her.
Back at the victim’s apartment, Hun Gi and Hae Young process the scene, while Gye Chul interviews subjects. Their investigation is interrupted by detectives from the Gyeonggi police department. Gye Chul is initially friendly with them, but they’re scornful of him and order everyone out of the crime scene. Hae Young starts baiting the lead detective until it devolves into a fight, while Hun Gi takes the opportunity to go back and keep investigating the body.
In the meantime, Soo Hyun shows up and stops the fight, then tells her team to pull out. Gye Chul and Hae Young are both shocked, but comply in the end. As they leave, Hae Young chases Soo Hyun and repeats what the Gyeonggi detectives said, that the victim had died, because of their investigation. Soo Hyun tells him that it’s her job to be in the thick of things while he views the case from a cold distance as a profiler. Instead of listening, Hae Young vows to put everything back the way it was using the radio, and to save the victim. Soo Hyun has no idea what he’s talking about as he walks away.
Hae Young pulls over by the side of the road, and writes down the information of the next murder, waiting for the time to hit 11:23 so he can talk to Jae Han. In 1989, Jae Han is being questioned by the detectives, who become suspicious of his intentions and end up locking him up. As the time hits 11:23, Jae Han’s radio goes off, but Jae Han is still locked up and can’t answer. Jae Han yells frantically for someone to listen, telling them that Hae Young is the one who gave him all the information, but his only guard is sound asleep. Hae Young tells Jae Han that another murder has happened in 2015, but Jae Han won’t listen until Hae Young gives him the name of the next victim, Kim Won Kyung, who turns out to be the woman Jae Han has a crush on. Hae Young tells him that she’ll die the next day at 9:30 on the streets of Hyunpoong-dong and begs Jae Han to catch the killer. Back in 1989, Jae Han goes crazy wanting answers, but the radio switches off.
Jae Han starts yelling, begging for them to let him make a phone call to Kim Won Kyung, to see how she is, but when the lead detective returns, he refuses to listen to Jae Han or even check on Kim Won Kyung.
In the present, Hae Young spends the night in the office, only to find that nothing has changed when he wakes up. He doesn’t have much time to be disappointed, as the other members of the team arrive. Soo Hyun has some good news, as she points out that the Gyeonggi team is already running into problems with their investigation, since there’s no CCTV and no witnesses. Instead, their own team now has one key piece of evidence, that this new victim was killed and then tied up, whereas the original victims were tied up and then killed.
Soo Hyun points out that the two murders are probably related, and if they catch the current murderer, they will have solved their own case. Inspired by her words, Hun Gi pulls out a broken glass cup that he found under the victim’s body, while Gye Chul realizes that he saw delivery trucks in the area that had black box cameras. Both men go rushing out, while Soo Hyun and Hae Young start going over the evidence they have. They conclude that the killer had to have been someone the victim knew, since there was no evidence of forced entry, and all the windows were locked. Soo Hyun is suspicious of the bus driver, but Hae Young dismisses the idea, since all the profiles made of the killer put him at 23 years old at the most.
In the meantime, Gye Chul manages to get the black box camera footage out from under the noses of the Gyeonggi detectives, and calls Soo Hyun. She goes to meet with the bus driver, and sends Hae Young to go view the footage.
In 1989, it’s two hours from the time of the murder, and Kim Won Kyung is still at work. Jae Han tricks his guard into coming into the cell, and then puts him in a sleeper hold to knock him out, apologizing as he does so. Jae Han grabs the radio and runs frantically out the door, to find Kim Won Kyung. He runs to her home, but discovers that she’s working late, so he runs around the streets calling her name. It’s 8:45 when he stops to check his watch, and the episode ends.
Does anyone else think that Soo Hyun knows something about the radio transmissions? It seemed like she reacted when Hae Young mentioned his radio, though she didn’t say anything at the time.
But, the person I really feel bad for is Jae Han, who has had a miserable three episodes, and has now found out that the girl he likes may be the next victim, but may not have enough information or time to save her. If he spends the entire 16 episodes of this show chasing his own tail, while Hae Young hands him tiny bits of information that may or may not help him, it’s going to be a frustrating series for all of us.
As for Hae Young, I’m not sure if the contrast between his emotional, and occasionally abrasive, personality and his ability to cut through the facts is intentional. Is he the type that makes intuitive leaps rather than someone who coldly analyzes the facts? At the moment, I’m having trouble pinning him down, because he still feels like a half-formed character. I’m having the same problem understanding Soo Hyun, and it’s not helped by her stoic personality. But, this is not necessarily a negative point; I like how the story is unfolding so far, and I trust the writer to give us more about both characters when we need it.
On a final note: I decided not to look up information about the Gyeonggi Nambu murder case, so as not to ruin the show. That said, I’m a little curious as to what watching “Signal” is like in Korea where the details are likely common knowledge.