After one last, heartbreaking kiss, Jung-hyuk finally succeeds in sending Se-ri back to South Korea. A short time later, she shows up at the Se-ri's Choice building, stunning all of her employees by being alive, and offering a huge sale on all of her products for the first time in the history of the company.
It happens to be the day when the board of directors will be voting on whether to appoint Sang-ah, Se-ri's sister-in-law, as the new CEO of Se-ri's Choice. Making her way to the boardroom, Se-ri runs into Secretary Hong, who bursts into tears to see her alive and well and grabs her in a huge hug, making her crack her Tough Boss expression and smile a little.
Just as the board members are all voting on favor of the change and Sang-ah is simpering in victory, Se-ri walks into the room and gives them the shock of their lives. She takes pity on the board members and sends them scurrying back to work, then tells Sang-ah that she'd always pegged her as impatient and greedy.
At the DMZ, the ducklings are back to their regular patrol schedule. But they're worried about Jung-hyuk, who hasn't been eating or sleeping well since Se-ri left. He spends time thinking about his last day with Se-ri, and after dark, he's approached by a very tentative Man-bok.
They go somewhere private to talk, where Man-bok tells Jung-hyuk that he's spent his whole life listening to others and never gets to talk about himself. But he says he once met someone who listened to him, and he shows Jung-hyuk the wallet his friend gave him as a birthday gift. Inside is a note wishing Man-bok a happy birthday, and signed by Moo-hyuk.
We flash back to ten years ago, when the swine flu was raging through the area. Man-bok's son, Woo-pil, was an infant at the time and became very ill, but the hospital was out of medicine. Moo-hyuk had shown up at Man-bok's house with medicine and a nurse and saved Woo-pil's life, and although Man-bok hadn't been able to pay him back for it, Moo-hyuk had taken what money Man-bok could offer as an acceptance of his gratitude.
Very soon after that, Man-bok had been ordered by Chul-kang to wiretap Moo-hyuk and listen in on him. Man-bok had balked, but his mother had been arrested for trying to cross the border, and Chul-kang had promised to get her out of prison. Man-bok had heard Moo-hyuk discussing Chul-kang and his crimes, and how he was planning to take the evidence to the Trial Bureau in Pyongyang. Moo-hyuk had had one chip with the evidence on them — one he was carrying to the Trial Bureau, and the other he'd hidden inside his watch.
It had been Man-bok's job to alert Chul-kang to Moo-hyuk's position so he could send his armored trucks to kill him. When he arrived home later, his wife had given him a birthday gift that Moo-hyuk left for him, with a note inside (and his money returned, aww) asking him to have a drink together when Moo-hyuk returned from Pyongyang. When he read the letter, Man-bok had wailed his grief for the only friend he'd ever had.
Now, Man-bok tells Jung-hyuk that he's always told himself he had no choice, but he never felt any better. He sobs that he misses Moo-hyuk, then he gets on his knees and says he wants to pay for what he did. He asks Jung-hyuk to take care of his family if anything happens to him, and he hands over Moo-hyuk's watch and a recording of the night Moo-hyuk died.
Jung-hyuk listens to Moo-hyuk talk about how proud he is of his brother's piano ability, and how much he was looking forward to hearing the song Jung-hyuk wrote for him. Jung-hyuk breaks down as he hears the truck crash, sobbing over and over that he's sorry.
In the morning, Wol-sook finds a letter from Se-ri in her salt crock, which explains why she had to lie about her real identity and thanks them for being her friends. The village wives are shocked to learn that "Sam-sook" is actually the famous CEO of Se-ri's Choice, and awww, it's obvious they miss her a lot.
When Se-ri has been back for two weeks, she goes to her father's house for a family dinner. Hye-ji gushes over her, and Se-ri clasps Hye-ji's hands…and reclaims the ring that Hye-ji swiped from her dressing room, ha. Hye-ji immediately tattles on Se-ri's stepmother for letting them into Se-ri's apartment.
Hurt, Se-ri confronts her stepmother, who (along with Sang-ah) bought up most of her company's stocks when the price plummeted after the announcement of Se-ri's "death." She warns Stepmom that the company belongs to her, not her stepmother's children. She says sadly that Stepmom must have been glad Se-ri was supposedly dead, and apologizes for disappointing her.
Stepmom gets out of dinner by claiming to feel sick. Se-ri fakes amnesia and lets her family think she's been in the hospital since her accident, though she says she remembers quite clearly up to their father choosing her as his successor.
Back at home in her luxurious apartment, Se-ri delights in the conveniences of her cushy South Korean life like stable electricity and hot water, and she rededicates herself to living like the young, wealthy woman she is. But at one point she starts to say something to Jung-hyuk, and when she remembers he's not there, all the happiness drains out of her.
Meanwhile, Jung-hyuk takes the microchip out of Moo-hyuk's watch and pulls up the incident report his brother had compiled on Chul-kang. He looks over it (it's absolutely terrifying), then sends it on to his father.
Seung-joon is about to meet with CEO Jeon when he's stopped by some scary-looking government men who say there's been a report about him, and they want to verify his identity. Luckily they run into Dan, who calls him Alberto and says she was going to call him, and her uncle, Colonel Go, who pulls rank and says that if Dan vouches for Seung-joon then he's legit.
Later, Seung-joon gets upset when Dan says she wasn't really planning to call him, since he's done so many favors for her like carrying her home the night she was drinking. He says she even invited him to sleep over, and Dan reacts with dainty horror, insisting that she never did any such thing, ha.
Seung-joon asks if Dan and Jung-hyuk are still getting married since he's in the DMZ, and she demands to know where he heard about that, since it wasn't from her. He's forced to admit that after dropping her off at home that evening, he'd gotten a call from Jung-hyuk.
Seung-joon had told Jung-hyuk honestly that Se-ri's brothers didn't particularly want her back because of the professional threat she posed, and had proposed keeping her in North Korea. But Jung-hyuk had argued that she belongs in South Korea and wanted to go home, and he'd asked Seung-joon for his help.
Seung-joon had protested that he actually barely knows Se-ri, who broke their engagement just weeks before the wedding, but he'd found himself helping anyway. We see now why nobody was seen entering or leaving Director Ri's house the night that Se-ri and Jung-hyuk left — Seung-joon had distracted the security guard by pretending to be lost, allowing Jung-hyuk and Se-ri to slip away on foot.
Seung-joon had driven them back towards the DMZ, pouting the entire way at Se-ri's gratitude and the knowledge that she pawned the expensive ring he gave her in order to buy Jung-hyuk a gift. Eventually Seung-joon had handed off the fugitives to Kwang-bum, and he tells Dan that he doesn't know what happened to them after that.
Dan is upset to learn that Jung-hyuk volunteered for duty at the DMZ again just for Se-ri, and Seung-joon says that he helped them, in part, so that she could end her futile yearning for her first love. Dan says it won't work, but Seung-joon says (very kindly, for him) that when the man you love risks his life for another woman, it's game over, adding that hanging onto something that even she thinks is pathetic isn't love, it's obsession.
Director Ri acts on the information sent to him from Jung-hyuk, and soon Chul-kang is put on trial for his crimes. He's prosecuted for arranging six murders disguised as accidents, as well as bribery, sale of stolen artifacts, and drug trafficking.
Chul-kang stays sullenly silent until Jung-hyuk testifies that the evidence came from his late brother, who was one of Chul-kang's victims, then he says that Jung-hyuk is trying to slander him and the accidents were just accidents. Jung-hyuk shows the judge the piece of ceramic composite material he took from the Engineer Brigade that's used to make the special truck armor, and testifies that the evidence proves Chul-kang's involvement in smuggling the material into the country.
Chul-kang begins to talk about Se-ri, and how Jung-hyuk helped her return home, but by now he just sounds like a ranting lunatic and the judge doesn't even listen. He finds Chul-kang guilty of all charges and sentences him to life in prison doing hard labor with no chance of appeal. Chul-kang lunges at Jung-hyuk and gasps that there's something he missed, and that because of it, Se-ri will die.
Worried, Jung-hyuk goes back through all of Moo-hyuk's compiled evidence against Chul-kang for something he missed. What he finds is a discrepancy between the amount of smuggled materials, and the amount of confiscated ceramic armor – which means that there must be two manufacturing places, and the armor is still being made.
Meanwhile, another armored truck is dispatched from the secondary manufacturing location to intercept Chul-kang's transport to prison. The transport truck is forced into a tunnel and the guards killed, and Chul-kang is rescued.
The following day, Jung-hyuk finds an envelope on his desk, which contains a copy of the article announcing Se-ri's death (that was previously published). It's a clear threat, and a call from Chul-kang confirms Jung-hyuk's worst fears — Chul-kang is alive, and he's going after Se-ri. Jung-hyuk swears on his brother's life that he'll catch Chul-kang.
Secretary Hong tells Soo-chan (who looks much better now that Se-ri is back and he's not scared of having to make such a huge insurance payout) that he's worried about Se-ri since she returned. She'd told him to take breaks sometimes when before her motto was "You can sleep when you die," and she'd taken him to the border and burst into tears when he said he didn't see anyone on the mountain.
While Man-bok is working, he's summoned to a dark, dingy room. At the same time, the ducklings are stopped at gunpoint during their patrol by several soldiers.
Se-ri leaves work late, and she doesn't see Chul-kang watching her in the parking garage, wearing a security uniform. At home, she can't get to sleep and she's out of sleeping pills, so she gets up to go for a walk. As she wanders the streets, she wonders to herself:
I wonder which one is love… hoping that you're worrying about me like I am for you and pining for me like I am for you, or is it wishing that you won't be worried about me, and that you'll forget about me and all the moments we've shared? Is that love? Or is it love that I'm willing to go through everything from the very beginning just so that I can meet you again?
Ahead of Se-ri, the crowd parts, and she blinks to see Jung-hyuk standing there. When he sees her, his expression goes soft in that way it does whenever he looks at her. It begins to snow and Jung-hyuk approaches Se-ri, and he says that he's been looking for her everywhere, since she only mentioned her neighborhood and not her exact address.
Se-ri just stares, unable to believe that Jung-hyuk is in Seoul, standing in front of her.