In an interrogation room, dock worker, Jang Il Joo, readily confesses to killing and trying to dispose of his co-worker to genius criminal profiler and possible psychopath, Lee Hyun (Seo In Guk). As Hyun prompts him, Il Joo adds that he had been disposing of murdered bodies for a mysterious person, whom he only knew by voice, for some time.
As Il Joo is led away through the office of the police, he pauses as he hears the voice of cold-blooded attorney, Jung Sun Ho (Park Bo Gum). Still in the interrogation room, Hyun wonders if these murders are the work of his younger brother, Min, while Sun Ho (whom we now know to be Min) smiles a creepy smile back in the office.
Hyun walks into the office of planning officer, Hyun Ji Soo (Im Ji Eun) to confront her about withholding the truth of Min’s disappearance. Before she can give an answer, they’re interrupted by Deputy Commissioner Kang (Nam Kyoung Eub), who assures Hyun that they searched as long as they could before declaring both Min, and his serial killer kidnapper, Lee Joon Young (Do Kyung Soo or EXO’s DO) dead. Hyun is not impressed with this reassurance and goes to leave. Before he can, Deputy Commissioner Kang asks Hyun if he believes Joon Young and his brother to be alive. Hyun is noncommittal, and leaves as Deputy Commissioner Kang and Ji Soo shoot each other a worried look.
As Hyun walks through the office, he muses that both Joon Young and Min must be somewhere in his immediate vicinity. On his way out, he passes by Sun Ho, and invites him to dinner in order to get to know him better. Sun Ho looks happy, but his smile turns creepy when he walks away.
That night, back at his house, Hyun watches a movie in English with police detective, Cha Ji Ahn (Jang Na Ra). He ignores her when she asks to turn on the subtitles, but after the movie, he asks her if she still believes her father is alive. Ji Ahn immediately intuits that he’s thinking about Min, and reassures him that he’ll find his brother if he believes hard enough. In voice over, Hyun confesses that he’s more worried that his guess might be right (i.e. that Min has become a serial killer). Hyun tells her to stay at his home until they catch her attacker, but doesn’t answer when Ji Ahn wonders what will happen if they never catch him.
The next morning, a woman feels a disturbance in the force while she’s out for a run, and looks back to see who’s behind her. It turns out to be medical examiner, Lee Joon Ho (Choi Won Young) out for a run with Hyun. When Hyun compliments Joon Ho on his fitness, Joon Ho points out that he has to stay in shape, since the damp weather will bring him many corpses. Hyun is mildly disturbed by Joon Ho’s turn of phrase, but keeps running. Meanwhile, the woman senses another disturbance in the force, but continues her run. Later, we see a body lying in the grass under an overpass.
Meanwhile, back at the house, Ji Ahn indulges in some idle snooping and turns up Min’s old sketchbook. She spots the same logo in it that was on the painting in the apartment of the first murder victim, but she’s interrupted by the arrival of Hyun. Ji Ahn hurriedly puts the notebook back and pretends to be exercising, then demands to know the menu for breakfast.
Later, as they do the dishes, Ji Ahn thinks back to all the times that Hyun has mentioned Min, then flashes back to when Hyun told her he didn’t know what he was looking for, and that he’d maybe be better off not finding it. Ji Ahn accidentally says, “Perhaps,” out loud, prompting Hyun to demand to know what she’s thinking. Ji Ahn is wondering if he found what he’s looking for, but Hyun hasn’t even yet decided to look for it. In voice-over, Ji Ahn wonders whether he believes Min might be involved in the killings, but their conversation devolves into a contest of getting soap on each other’s faces.
At the prison, Sun Ho asks Il Joo how he knew to hire him as a lawyer. Il Joo is flustered, but explains that he heard about him in jail. Sun Ho drops all pretense and asks Il Joo why he opened the box without permission (referring to the crates of bodies that he was meant to dispose of). Il Joo is even more flustered at this direct attack, but Sun Ho quickly moves on to what Hyun asked him. Il Joo reveals that Hyun showed him the picture of prosecutor, Shin Jang Ho, and asking if he was the last body. Sun Ho flashes back to when Hyun was knocked unconscious while visiting Jang Ho. It’s now revealed that the mysterious attacker was Sun Ho.
Back at home, Hyun sits in the basement and contemplates Il Joo’s bank book. The dates where Il Joo received a box to dispose of, and money in his bank account all match the dates when Hyun made brief trips to Korea. He shakes his head to dismiss the idea that it was more than just coincidence.
Veteran cop, Son Myeong Woo (Min Sung Wook) is on a blind date with Hyun Sook, the woman shown earlier out on a run. He’s totally awkward, but instead of small talk, she tells him that she believes she’s being stalked and asks for help.
His overly enthusiastic offer of help is overheard by Bong Song, Hyun’s art dealer friend, who happens to be having his coffee in the same place. When Bong Song looks around, he spots Myeong Woo, and remembers him from the batch of photos that Hyun told him contained a serial killer. When Myeong Woo sees him staring, he confronts Bong Song in front of the washroom. Then, Myeong Woo returns to Hyun Sook, but she rejects him as useless and leaves, much to Bong Song’s satisfaction. Myeong Woo is too caught up in his heartbreak to notice when a guy follows Hyun Sook out the door.
Back at the police station, Myeong Woo’s troubles are compounded when he discovers that Hyun has been assigned the desk facing his. Ji Ahn, cheerful rookie, Min Seung Joo (Kim Jae Young), and geeky cop, Choi Eun Bok (Son Seung Won) all look on as Myeong Woo and Hyun face off, but they’re interrupted by the arrival of team leader, Kang Eun Hyeok (Lee Chun Hee). Eun Hyeok informs them that a woman’s body has been found and they all get ready to leave.
The victim in the case turns out be the body from under the overpass. Hyun and Ji Ahn discuss the murder with Joon Ho, who points out where the woman was tortured. Joon Ho tells them that he’s seen a case like this before, much to Hyun’s satisfaction. Hyun’s happy to have a serial murder to work on, but Ji Ahn warns him to dampen his enthusiasm in front of the other cops.
Back at the police station, the team works together to find the murderer, with Hyun mapping the events, Eun Bok looking at previous cases, and Myeong Woo reviewing the CCTV footage. Joon Ho calls in to tell them that the body had a week-old injury, likely from the initial abduction. The team quickly pulls together a pattern of four similar murders that occurred one week after the initial abduction.
Meanwhile, Hyun Sook wakes up from a nap in front of the TV to discover a hidden camera filming her. She runs out of the apartment and tries to call Myeong Woo, but he doesn’t answer before she’s picked up by a black van. Back at the police station, Ji Ahn reports that the second victim reported being stalked to the police. Myeong Woo finally clues in that Hyun Sook is in trouble, and goes tearing off to her apartment with Seung Joo in tow.
Back at the police station, Hyun points out that the time between murders is getting shorter, since the murderer is gaining confidence. Hyun asks Ji Ahn for insight into the mind of the stalker, since she’s a stalker herself. When Eun Hyeok wonders what they’re talking about, Ji Ahn explains that she’s an idol fan, to Hyun’s amusement. Instead, Ji Ahn points out that they likely have a time limit of one week to find Hyun Sook, since that’s how long the other murders have taken. Hyun disagrees, since the the pattern of abductions has accelerated.
Meanwhile, Hyun Sook wakes up tied to a chair in a garage. She screams for her attacker, who turns out to be a woman (Lee El), who shushes her.
At Hyun Sook’s apartment, Myeong Woo and Seung Joo find the camera, and figure out that whoever installed it must have access to the master keys. When they question the landlady, she takes offence at this suggestion, but the culprit turns out to be her son, Soo Yong. After a search of Soo Yong’s apartment, they turn up some of Hyun Sook’s belongings. In an interrogation, Hyun establishes that Soo Yong is suffering from De Clerambault Syndrome, and believes himself to be in a relationship with women who are nice to him. The other victims have all been Soo Yong’s past “girlfriends”.
Back in the office, Ji Ahn volunteers to be the one that interrogates Soo Yong, since he likes women. She tries to come on to him, but he ends up rejecting her since she’s not his type. Instead, Ji Ahn takes his hand and plays up to him as a fellow stalker, and points out that his girlfriend’s life is on the line. When Soo Yong starts responding to her overtures, back in the viewing room, Hyun and the other detectives can barely contain their rage. But, it gets results as Soo Yong confesses that whenever he shows off his girlfriends, they disappear into a black van driven by a big man with a star on his head.
Interview over, Ji Ahn repeatedly washes her hands, but when she comes out, she still feels icky. Lucky for her, Hyun holds her hand in his to make her feel better, and tells her that the feeling will go away. Ji Ahn shakily agrees.
Meanwhile, the detectives find a record of Soo Yong uploading his recordings of the women onto an international porn site, meaning that the culprit could be any one of thousands of people.
In his office, Sun Ho thinks back to Hyun’s dinner invitation and calls him. The conversation is stilted and formal as Sun Ho invites himself over to Hyun’s house, and Hyun reluctantly agrees.
Hyun goes back to the office, where the other detectives are sound asleep, and with Ji Ahn, talks over his theories of the case. Hyun believes that the murderer must regularly use the road where he disposed of the bodies, and that he has enough money to have a second car and a place where he can confine women for a week. Myeong Woo wakes up long enough to take in what they’re saying, and then goes back to sleep as Hyun leaves to prepare dinner for Sun Ho.
Ji Ahn, meanwhile, continues to look into the case, and comes to the conclusion that the first victim’s boyfriend matches Hyun’s profile. She and Eun Hyeok decide to interview him, with the excuse that they’re collecting statements from friends and family. On the way there, Eun Hyeok confesses that he feels guilty for not catching Ji Ahn’s attacker, and that he’ll dedicate himself to that case when the current one ends. Ji Ahn is reluctant, since she knows her time at Hyun’s house will come to an end when her attacker is caught.
At the boyfriend’s large and fancy house, Ji Ahn and Eun Hyeok barely get a word in edgewise as the boyfriend accuses the police of treating him like a suspect, and tells them to contact his lawyer. On their way out, Ji Ahn spots a license plate peeking out from under a half-open garage door. They sneak in to find a black van, with a star sticker on the driver’s side windshield. Eun Hyeok confirms that the license plate is fake, and it seems that they’ve caught their criminal.
Back at Hyun’s house, Sun Ho arrives with a gift. As Hyun cooks, Sun Ho looks around, and thinks back to his childhood when Hyun cooked for him. He offers to help Hyun out, but they’re interrupted by the arrival of Hyun’s other guest, Joon Ho.
Back at the garage, Eun Hyeok is about to call for backup, when the garage door opens fully to reveal a huge man. He immediately goes on the offensive, and Eun Hyeok grapples with him, only to be thrown around like a rag doll. When the man pulls a knife, Ji Ahn fires a round into the air to stop them. Her triumph is short-lived as Ji Ahn is hit from behind by the woman who kidnapped Hyun Sook. When Eun Hyeok tries to stop her, he gets stabbed in the belly. Eun Hyeok watches helplessly as the huge man picks up Ji Ahn, and the episode ends.
I promised earlier not to nitpick over details, so I’ll confine myself to one: is it me, or is Hyun Sook tied by the hands to a folding chair? I am no expert on rendering my victims immobile, but even I would think to tie her legs to something a little more sturdy. But, then, maybe I’m just devious like that.
That aside, I don’t have too many comments. Hyun holding Ji Ahn’s hand after the interview was pretty dreamy, as was the fact that, unlike Eun Hyeok, he didn’t comment on how she shouldn’t do the interview since she’s a woman, though it obviously bothered him.
And, the cliffhanger they’ve left us on is pretty good: Ji Ahn has just been kidnapped while Eun Hyeok is down for the count with a knife in his gut. Possibly worse might be Hyun’s situation, eating dinner with two people that the show has been baiting as serial killers. So, either we’re being trolled, or the next episode is going to bring us some revelations about Hyun’s past. At the very least, maybe Hyun and Sun Ho can get past the point of their stilted and overly formal conversations; even watching them on TV makes me cringe a little.
On a final, more shallow note, I prefer Hyun’s hair up. Can somebody get on that, please?