Flashback…2005…summer…Do Hyun Soo wakes in a strange bed and room after being hit after running into the road on a dark rainy night. With his lower leg in a cast he hobbles down the stairs. He sees the Baek family photo above the fireplace. He makes his way to the jewelry stash in the Baek's walk in closet. He's startled when Baek Man Woo opens the secret door and finds Hyun Soo stealing. Gong Mi Ja follows her husband out the secret door and sees Hyun Soo's hands full of her jewelry. Hyun Soo flees. Ms. Baek tell her husband they must catch Hyun Soo. Mr. Baek puts down a tray of bloody cloths and follows Hyun Soo.
Cha Ji Won watches her husband sleep.
Flashback…Hee Sung and Ji Won makes love the night before.
Ji Won wonders why her husband has made the choices he's made. She only wants a reason to forgive his lies. Hee Sung wakes to find her watching him. He's surprised he's slept so late. He admits coming home is a relief. Ji Won gives Hee Sung a new watch. He loves it. She chides him not to lose this one.
Before Ji Won takes Baek Eun Ha (Hee Sung's daughter) to school she admits that she broke the lock in Hee Sung's shop's basement. She lies why she broke it. She takes Eun Ha to school.
Ji Won requests the official records of her husband's family.
The video of Reporter Kim Moo Jin interviewing the witness and the recording of the murderer garners 1.5M view. Everyone at work is thrilled.
Ji Won studies the family registry. She knows that her husband has masqueraded as Hee Sung for 14 years with the help of Mr. and Ms. Baek. She wonders why. She overhears students listen to Moo Jin's video. Ji Won listens to the video too.
Flashback…May 12, 2002…Ms. Jang, the witness, hits a man's car. She apologizes and hopes he'll settle. He asks for her phone number and gets back in his car. Ms. Jang is startled when the back door opens and Jung Mi Sook spills out of the car. She limps away. The man goes after her. He calls her his wife, tells her not to drink so much, and helps her back into the car. Ms. Jang memorizes the license plate.
On a broadcast, Moo Jin reports the car belonged to Do Min Seok (Do Hyun Soo's Father). He notes this is where Hyun Soo provided a movie alibi for his father. The witness was doubted because she was under the influence.
Do Hae Sue (Do Hyun Soo's sister) sees the broadcast. Moo Jin shares the fingernails of victims including Ms. Jung were found in Do Min Seok' workshop. This closed the Yeonju serial killer murders. Hyun Soo fled after he killed the village foreman. Mr. and Mrs. Baek watch the broadcast. Moo Jin states an accomplice began threatening the witness so she recanted. They play the voice recording of the man threatening the witness. The man states the village foreman died because he was nosy. Upset, Do Hae Sue runs away.
Hee Sung replaces the lock on his basement door. He finds his wife watching the broadcast with Moo Jin. She offers to paly the voice recording of the man for her husband. He declines. She suggests they meet tomorrow afternoon. He smiles and agrees. Ji Won heads to bed.
Hee Sung listens to the recording of the man.
Moo Jin celebrates his success with coworkers with drink and song. He checks his phone and reports he has 200K followers. Hee Sung calls and complains that Moo Jin implied Hyun Soo was the accomplice. He wants the option of a 3rd person investigated. Moo Jin retorts he doesn't take orders. Moo Jin says Hyun Soo is the prime suspect. Moo Jin doesn't care about Hyun Soo offer of help. He points out he can't trust Hyun Soo.
Police management try and decide what to do about the case.
Officer Im Ho Joon tries to interest Detective Choi Jae Sub in solving the lettuce thief case. It's a hard sell.
Ji Won watches video of a young Hyun Soo discussing his cruelty to a dog.
Hyun Soo visits Mr. Baek. He notes not killing Mr. Park should be considered a positive. Mr. Baek plays the recording. He asks if it is Hyun Soo who denies it. Mr. Baek doesn't believe or trust him. Hyun Soo repeats not killing is a positive. Mr. Baek wants Hyun Soo to agree to disappear if his real identity comes to light. He promises to take care of Ji Won and Eun Ha for the remainder of their days. He reminds Hyun Soo of what could happen.
Moo Jin's boss wakes him at work. She points to Do Hae Sue waiting to speak with him. Moo Jin is dismayed he looks and smells awful after drinking all night. Recall he used to date Do Hae Sue. He admits this to his boss. He hasn't seen her in 17 years.
Ji Won watches a young Hyun Soo state he wanted to get rid of the dog's owner but couldn't bury a man's body. Ji Won asks if Hyun Soo had an antisocial personality disorder. She watches another tape where Hyun Soo hits another classmate over the Walkman. She learns Hyun Soo was touchy about the Walkman.
Ji Won takes the bag that Mrs. Nam gave her of Hyun Soo's items. She confirms the Walkman is still there. She leaves.
Ji Won listens to the tape in the Walkman with the fish charm. She calls Mrs. Nam who states Hyun Soo was touchy about the Walkman. Their call breaks up due to bad connectivity.
Moo Jin is awkward around Do Hae Sue. He remembers what she used to be like. She counters that finding out her father was a serial killer changed everything. She shares she was recently fired. She asks Moo Jin to leave because a reporter is following her. She wants to talk to him in private.
Hyun Soo listens to the voice recording.
Ji Won puts the Walkman on the table where Hyun Soo used to work and tells his former boss there's a tape.
Flashback…The former boss given an arm twist when he tries to listen to the tape in Hyun Soo's Walkman. Hyun Soo warns him not to do that again.
The boss says Hyun Soo would get a strange look in his eyes when he listened to the tape.
Mrs. Baek is surprised when Ji Won's mother drops off Eun Ha for babysitting. Eun Ha assures her grandmother she'll be doing schoolwork. Mrs. Baek tears up Eun Ha's schoolwork declaring it too advanced. Eun Ha cries. Mrs. Baek asks what she wants. Eun Ha declares she wants an egg tart.
Hyun Soo listens to the voice recording. He hears tapping in the background. Ji Won arrives. She puts his bag on the table. They sit. She says this is Hyun Soo's bag that Mrs. Nam gave her. Ji Won says she's going to catch Hyun Soo. Hee Sung asks how she can catch him with only a bag. She pulls out the Walkman with the fish charm and a sketch book. Hyun Soo can't take his eyes off the Walkman but reaches for the sketch book. Ji Won thinks she can lie with ease just like her husband. She tells him that Hyun Soo might be a metal artist now. She asks her husband to help her find artists that make similar designs to those in the sketch book. Hee Sung glances at a piece that has an identical design to one in the sketch book. He claims he'd need to see the real work not just sketches. Ji Won suggests he comes with her to Do Min Seok's workshop. Having no choice, he agrees. She tells him to close up shop and join her in the car. She leaves the shop. Hyun Soo tries to get a grip.
Mrs. Baek buys Eun Ha an egg tart. Eun Ha says she won't tell her father she ripped her schoolwork. Mrs. Baek is drawn to Eun Ha.
Ji Won explains the theory is that Hyun Soo is the Yeonju serial killer's accomplice. She says she'll get a promotion if she catches him. Hee Sung claims to be surprised his wife wants this. She smiles and notes everyone wants to advance.
A nervous Moo Jin brings Do Hae Sue to his apartment. He pours wine. He puts on music and says he'll cook a quick meal. He admits he thinks about her sometimes. He believes her father and brother destroyed her life. She downs the wine. She tells Moo Jin the recording isn't her brother's voice. Moo Jin sighs that her brother doesn't care about her. She admits she killed the village foreman. Moo Jin is shocked.
I'm not shocked by that statement.
Ji Won and Hyun Soo arrive at Do Min Seok's workshop. She admits going in there will be unnerving. Hyun Soo sees a carving on a tree.
Flashback…A young Do Hae Sue carves the tree then promises to find their mother if he eats well. Their father tells them to come inside. She agrees and instructs her brother to do as father says to avoid punishment.
Ji Won and Hyun Soo approach the workshop. It is locked. Ji Won finds an open window and enters. Hyun Soo has no choice but to follow. Ji Won scans the items on the table. She picks up metal turtle. Hyun Soo says the work is okay but not good. Ji Won says she wants to go to where the village foreman was murdered. Hee Sung asks why. Ji Won says she can go alone. Hyun Soo agrees to go. They enter the basement. The cage is on the floor. Hyun Soo reacts to the smell of blood. There is a cage on the floor. Inside are dog leashes. With Hyun Soo's back to her, Ji Won removes the Walkman and plays the tape. It is someone humming. She asks if the girl's voice sounds sad. Hyun Soo sees the fish charm hanging from the Walkman. Ji Won explains this was in Hyun Soo's bag. Ji Won explains this tape triggered Hyun Soo to become violent but no one knows what the humming tape is about. Ji Won believes the humming tape was recorded here. She puts the Walkman on a table. She wonders if Do Min Seok forced his son to deliver food and water to his captives. Hyun Soo says he wants to leave. Ji Won delays saying someone is meeting them there. She says the eatery owner and boss where Hyun Soo used to work is coming with sketches made by Hyun Soo. Her phone rings. Hyun Soo struggles to keep it together. The eatery owner calls and says he'll be there soon. Ji Won observes her husband struggling. She thinks his choice will determine the rest of their lives. Hyun Soo drops the flashlight. He walks to his wife and pushes her against a wall. He struggles to keep it together. He puts his hand to her neck. Ji Won starts to retrieve her gun. He falls to his knees. He tells his wife he can't breathe. He says they must go.
Back in the car, Hyun Soo gasps for breath. He tells her he'll be okay. He wants to go home. Ji Won worries that she pushed him. Ji Won reminds herself that her husband has lied to her for 14 years. Hyun Soo asks where the person is that was coming.
Mrs. Nam says prayers for her husband at the temple. She's surprised when the owner at the eatery where he husband and Hyun Soo used to work arrives. He says he's there to pray for her husband. He asks where Detective Cha is. That surprises Mrs. Nam. He says he was going to meet her at the temple.
Ji Won calls him and says she'll meet him another time. Hee Sung tells her not to search for Hyun Soo. He says it is too dangerous. Ji Won declares she can't let Hyun Soo roam free.
Hyun Soo can't sleep. He recalls his father's request that he disappear if Hyun Soo is identified. He gets out of bed. Ji Won opens her eyes and looks at the closed door.
Moo Jin looks at the glass that Do Hae Sue drank from. He recalls her words that her family hurt him in the past. She apologizes. She tells him not to be angry at Hyun Soo. She killed the Yeonju foreman. She's willing to give him that exclusive if he'll stop pursuing Hyun Soo. Moo Jin puts his head in his hands. Hyun Soo arrives. He asks Moo Jin to help him find his sister. He returns the videotape and apologizes for blackmailing him. Hyun Soo says he needs to find that jerk. Little does he know his new watch has a tracking device.
Ji Won tracks her husband.