Episode 4 of "Love Next Door" kicks off with a poignant moment as Seok-ryu and Seong-hyo, finally unlocking the time capsule's mysteries, read their heartfelt letters, only to stumble upon a missing piece: Mo-eun's letter, absent without a trace. Amidst the revelation, Seong-hyo hastily flees home, his steps swift and determined, lest Seok-ryu snatches his secrets away. Later, he struggles to convince himself that his adolescent affections for Seok-ryu are but a distant memory, a charade that rings hollow to even his own ears.
As dawn breaks, the financial strains of Seok-ryu's family are revealed, while across town, Seung-hyo's mother prepares for an imminent departure, her patience wearing thin at her husband's repeated inquiries. Meanwhile, Seok-ryu, with time on his hands, finds himself lingering at Seong-hyo's burgeoning company, where Myung-u drops a bombshell: Greip, Seok-ryu's former employer, desires a collaboration. The offer, facilitated by Myung-u's U.S. connections, presents a linguistic hurdle as both parties struggle with the English language. Despite his discomfort, Seok-ryu valiantly steps forward as their interpreter.
However, the triumph is short-lived as Seok-ryu overhears the team's whispered confessions: they've secretly chosen another firm due to pressing deadlines and Seong-hyo's company's lack of an established record. Seok-ryu confides in Seung-hyo, who refuses to be deterred, insisting on giving it his all and pleading for secrecy from Myung-u.
Elsewhere, a comedic rivalry brews between Mo-eun and Dan-ho at the convenience store, their mutual obsession with rare flavors and products fueling a playful competition. When Seok-ryu and Seong-hyo stumble upon this unlikely duo, a lively chat ensues. Dan-ho learns of their childhood bond, but Mo-eun's inquiry into his past residence prompts a vague response and an abrupt exit, leaving the group puzzled.
As the friends trek home, curiosity prompts them to inquire about Mo-eun's absent letter. She reveals a surprising twist: she retrieved it that very night, yet claims to have forgotten the contents of Seung-hyo's missive. This confession leaves both Seung-hyo and the audience on the edge of their seats, wondering if truth or tact lies behind her words.
Elsewhere, Mo-eun's path crosses with an enchanting six-year-old girl, her eyes sparkling with wonder as she hunts for crop circles amidst the park's greenery. The child, a fervent believer in extraterrestrial life and a science fiction aficionado, mirrors Mo-eun's own youthful enthusiasm, instantly forging a bond between them. Later, Mo-eun regales Seok-ryu with tales of their encounter, her frustration palpable as she realizes she forgot to inquire about the girl's name. "I narrowly escaped losing my dearest friend to a chance meeting," Seok-ryu quips, a hint of amusement in his voice.
Meanwhile, Dan-ho lends a helping hand to Mo-eun's mother, a real estate magnate who had graciously assisted him in securing his abode. Just as Seok-ryu's mother enters the scene, captivated by Dan-ho's charm, she discreetly inquires about him, eyeing him as a potential match for her son. However, Mo-eun's mother, momentarily distracted, refrains from divulging a crucial piece of information regarding Dan-ho.
As Seong-hyo, Myung-u, and Seok-ryu stride towards the pivotal meeting, where Seong-hyo is poised to present their innovative proposal to Greip's representatives, Seok-ryu's composure falters upon encountering a former colleague now occupying the esteemed position of team leader. Memories of workplace harassment resurface, a bitter reminder of how she was once exploited and burdened with their collective workload. Moreover, whispers of her unexplained career hiatus linger in the air.
Shaken, Seok-ryu seeks refuge in the bathroom, only to encounter her tormentor once more. His disdainful gaze and mocking words cut deep, but Seung-hyo, ever vigilant, overhears the exchange and retaliates with a swift punch. Seok-ryu, her inner warrior unleashed, retaliates fiercely, threatening him with evidence of his misconduct. Together, the duo curses the perpetrator and his ilk, symbolically binding their hatred with love locks at the iconic Namsan Tower.
In a twist of fate, Myung-u shares exhilarating news: Greip has offered them an alternative job opportunity, enamored by their exceptional designs. He further reveals that Seok-ryu's former teammate has been dismissed, the result of Myung-u's strategic move—he had secretly recorded their conversation and leveraged his friendship with Greip's vice president.
Flashbacks paint a poignant picture of Seok-ryu's selflessness, skipping a crucial mock test to support Seung-hyo during his tournament. Dan-ho, ever the chronicler, captures this moment in a photograph, which he presents to Seok-ryu as a poignant reminder. Another flashback transports us to a heartwarming scene where Seung-hyo, traveling from Korea, surprises Seok-ryu with her favorite books, eliciting a heartfelt embrace.
The episode culminates in a tender moment, as Seok-ryu wraps her arms around Seung-hyo, congratulating him on his achievement with Greip. Seung-hyo, taken off guard, blushes profusely, their bond strengthened by shared triumphs and unwavering support.
