In 1989, police officer, Lee Jae Han (Jo Jin Woong) is frantically running through the streets of Hyunpoong-dong looking for his crush and next possible murder victim, Kim Won Kyung. Instead, he runs into Lee Chun Goo, the driver of Bus 95, the bus route that links all of the murder victims. Jae Han asks Chun Goo if he’s seen Won Kyung, and the bus driver wordlessly points back the way he came.
In the present, police detective, Kim Gye Chul (Kim Won Hae) views footage from the black box of a delivery truck that was in the area of the current murder case. Just as he identifies Chun Goo on the footage, his colleague, forensic expert, Jung Hun Gi (Lee Yoo Joon) comes in with fingerprint evidence that Chun Goo was in the apartment of the current murder victim, Jung Kyung Soon.
Meanwhile, police profiler, Park Hae Young (Lee Je Hoon) is at the bus company, asking about the victim’s employment record. When he discovers that some detectives have come before him, he decides to ask about Bus 95 as well. He’s referred to one of the drivers, an older man who was Chun Goo’s colleague. The man doesn’t have much information to give, except that Chun Goo quit after the murder of the bus attendant in 1989, because something happened to his son.
At the hospital where she’s looking for Chun Goo, detective Cha Soo Hyun (Kim Hye Soo) gets a call from Gye Chul, warning her that Chun Goo is the culprit. Already on his way to the hospital himself, Gye Chul calls Hae Young, telling him to rush to the hospital, too. Hae Young can’t believe that Chun Goo is the culprit, since he was driving the bus the night of the murder in 1989, and he was too old to fit the profile anyway. Hae Young asks his senior colleague how old Chun Goo’s son was when Chun Goo quit, and the older man tells him that he must have been about 20. Since he was sickly and motherless, the son used to ride along on Bus 95 all day, even when his father wasn’t the one driving. Hae Young imagines a scenario where Chun Goo finds the body of the dead bus attendant, and discovers that his son is the culprit. Gye Chul tells him that Chun Goo would do anything for his son, and Hae Young figures that he would even lie to the police.
Soo Hyun, meanwhile, cautiously approaches the room of Chun Goo’s son, her gun at the ready. She opens the door to find the bed of the unconscious Lee Jin Hyung (Lee Chun Goo’s son). In 1989, Jae Han is still frantically searching for Won Kyung, when he hears a scream. Back on the path, Chun Goo clutches at his chest in pain.
Back in the present, Soo Hyun gets a call from Hae Young, warning her that Chun Goo is not the Gyeonggi Nambu killer, but that he may have committed the current murder to cover up for someone. Before he can tell her who it is, Soo Hyun turns around to find Jin Hyung is awake. Before she can say anything, he grabs her and starts strangling her with the phone cord. As they struggle, both Hae Young and Gye Chul rush to the hospital, only to find that Soo Hyun has freed herself by bashing Jin Hyung’s head with a lamp.
Gye Chul has no idea what’s going on, and Hae Young tells him that Jin Hyung is the Gyeonggi Nambu serial killer. Jin Hyung denies it, saying that he was only defending himself against someone who was standing over him with a gun. In the confusion, Gye Chul gets a call from Hun Gi, telling him to turn on the TV, since Chun Goo has turned himself in as the Gyeonggi Nambu serial killer.
In interrogation, Chun Goo admits to everything, but Soo Hyun is adamant when speaking to her supervisor, Ahn Chi Soo (Jung Hae Kyun) that he’s not the killer. Unfortunately, she has no evidence that it’s Jin Hyung either. Chi Soo points out that given the level of media attention, no one will want to listen to anything the cold case squad has to say without concrete evidence.
Back at the office, Hae Young looks at the white board to see that nothing in the past has changed. When he goes outside to speak with Jae Han via the radio, Jae Han is withdrawn and only asks him if he caught the killer. When Hae Young asks what’s wrong, Jae Han demands the name of the killer. In fact, Jae Han was too late to save Won Kyung, and was only able to find her dead body. Devastated, Jae Han couldn’t even walk in the door of her funeral, and instead prayed outside. In tears, Jae Han swears to Hae Young to kill the man who did it. Hae Young begs him not to, and asks him to interrogate Jung Kyung Soon instead, since she saw who the killer was, but Jae Han is no longer listening.
Hae Young has a sudden flash and runs into the police station to toss out his latest theory. Hae Young figures that Jung Kyung Soon had something on Chun Goo that she was blackmailing him with. When the statute of limitations ran out, Jung Kyung Soon hid the evidence away, since she couldn’t use it against him anymore, but when they abolished the statute of limitations, Jung Kyung Soon would have gone to look for it again. Soo Hyun and Hae Young figure that if they can follow her tracks on the day that the statute of limitations was abolished, they can find whatever evidence she was holding over Chun Goo’s head. Gye Chul points out that the police superintendent is about to make an announcement, but neither Soo Hyun nor Hae Young are put off. Soo Hyun tells Gye Chul to look up her phone and credit card records, while Hae Young and Soo Hyun go to search Jung Kyung Soon’s apartment.
Gye Chul’s search comes up empty, but in the apartment, Hae Young quickly finds a ticket to Sunyang in her coat pocket. It turns out that Jung Kyung Soon had a cousin in Sunyang, and the two of them race over to the cousin’s house. Hae Young quickly finds a bag belonging to Jung Kyung Soon, and finds some piece of evidence inside that we don’t see. Directly after, Hae Young races to the bedside of Lee Jin Hyung, and exposes his shoulder to see a scar.
In the meantime, the superintendent has called a press conference to announce that they’ve finally caught the Gyeonggi Nambu murderer. Partway through, before he can identify Chun Goo as the serial killer, Soo Hyun bursts in and hands over some new evidence to the superintendent. He looks it over, and then hands over the press presentation to her. Soo Hyun announces that during the investigation into the death of Jung Kyung Soon, they found the evidence that led to the Gyeonggi Nambu serial killer.
At the police station, Hae Young goes into the interrogation room of Chun Goo, and we flash back to Jung Kyung Soon and Chun Goo being questioned by Jae Han shortly after the attempted murder. Jung Kyung Soon is quick to notice that Chun Goo is lying and points out that the young man with the black jacket could have been his son, Jin Hyung. Later, when Jin Hyung kills Won Kyung, Jung Kyung Soon is following behind, and finds the Taser that Jae Han had given Won Kyung.
At the press conference, Soo Hyun announces that the killer is Jin Hyung and holds up the Taser from which they gathered DNA evidence. Back in the interrogation room, when Hae Young confronts Chun Goo with pictures of his son’s victims, Chun Goo tells Hae Young that his son already paid for his crimes back then. We flash back to 1989, when an enraged Jae Han bursts into Chun Goo’s house, and comes face to face with Jin Hyung, in a black jacket and hat. Jin Hyung takes off, with Jae Han immediately after him, and after a chase through the streets, Jae Han catches him up on a rooftop. Jae Han starts beating Jin Hyung, but Chun Goo whacks him on the head from behind. Deflated, Jae Han realizes that Chun Goo will never testify that his son was the one who ran on the bus, and with no other evidence, he decides to kill Jin Hyung. As Jin Hyung runs away, he falls off the roof, but Jae Han catches him. Looking down into his face, Jae Han sees Jin Hyung smile, and just lets go of him.
Back in the interrogation room, Lee Chun Goo tells Hae Young that Jin Hyung has already paid for his crimes. Hae Young is stricken to learn that it was Jae Han who stopped the murders. We flash back again to 1989, when Jae Han visited the hospital to find Jin Hyung paralyzed. Jae Han tells Chun Goo that he’s going to turn himself in, and that Chun Goo and his son should turn themselves in too. Chun Goo refuses to do it, since his son will be bedridden for the rest of his life anyway.
In the present, Chun Goo tells Hae Young that they’ve suffered enough and wonders why anyone would dig up the investigation again. Hae Young turns the question back at him, asking him if he’d be able to forget if Jae Han had actually killed Jin Hyung.
Hae Young leaves the interrogation room, and walks out to the atrium, where Soo Hyun comes to join him. She advises him to find something to help him cope, pointing out that even though it’s the first time he’s seen a dead body, it won’t get easier with time. Hae Young responds by pulling back her collar to look at her injured neck, and remarking that a woman’s neck shouldn’t look like that. As he walks away, he tells her that it’s not the first time he’s seen a dead body.
Later, while working at home, Hae Young flashes back to his childhood, when his brother, Sun Woo was arrested for a high school gang rape case in Injoo. Shortly after, Sun Woo committed suicide, and Hae Young was the one that found his body. In the present, Hae Young looks at a photo of the two of them together. Meanwhile, Soo Hyun flashes back to the past, when she cried after the first time she saw a body. She was comforted by Jae Han, who confessed that everyone cried when they saw bodies, which is why they should catch the killers. Jae Han tells Soo Hyun to find a way to get over it, even crying so that she can do her job. In the present, Soo Hyun sits alone in the same stairwell where Jae Han comforted her, and cries.
The next day, Hae Young goes to visit the aunt of Kim Won Kyung, who assures him that Won Kyung can now rest easy. When Hae Young credits Won Kyung for helping them catch the killer, her aunt denies it and credits Jae Han instead. She tells Hae Young that Won Kyung liked Jae Han, and we flash back to the past when Won Kyung noticed him for the first time, refusing a bribe for a parking ticket. After Won Kyung’s death, her aunt came to Jae Han to tell him how much Won Kyung liked him, and to give him the movie tickets that Won Kyung had bought for the two of them.
That night, when the radio goes on, Hae Young tells Jae Han that they caught the killer, thanks to him. When Jae Han asks how they did it, Hae Young explains that it wouldn’t have been possible in his time for the evidence to be found (since it was DNA evidence on the Taser). Later, Jae Han uses the movie ticket and cries his way through the comedy that Won Kyung wanted to take him to.
In the present, watching the media circus surrounding the arrest of Jin Hyung, Won Kyung’s aunt also cries. Soo Hyun and Jae Han’s father watch the same media circus on TV, and dab at their eyes, while Hae Young stands on his rooftop with tears in his eyes.
I guess we can consider this a cliffhanger, because having finished the Gyeonggi Nambu case (or did we?), I have no idea where this show is going next. The trial, maybe? Another case? Maybe Hae Young’s brother’s case? The preview didn’t get into it, and I really don’t know. But, I do know that I’ll be back next week to find out.
But, let’s get into this episode. On a typical cop show, we would get some kind of showdown between our intrepid detective and the suspect, where the suspect finally breaks down in the face of incontrovertible evidence and admits to everything, a trope that’s taken to ridiculous extremes in something like “CSI”, for example. But here, instead of Jin Hyung being the focus of the investigation, the focus was squarely on the father that protected him, to the point of lying to the police, letting Jin Hyung kill again, and then murdering someone in cold blood himself.
This is one of those situations where I’d love to pick the writer’s brain. Is there a suspicion that family members protected the killer in the Gyeonggi Nambu case? Is this going to be a recurring theme on the show? The showdown in the interrogation room between Chun Goo and Hae Young wasn’t a particularly satisfying conclusion to the case, because Chun Goo came off as a deluded, overprotective father who had gone too far, and not as an evil criminal mastermind. This must have been a deliberate choice, because it made the detectives seem less like heroes and more like people who were doing a difficult job that took an enormous emotional toll. Simply arresting Jin Hyung would have made for a much less complicated ending. Kudos, writer, for not making “Signal” a straightforward cop show!