Episode 4 of "DNA Lover" unfolds with A-ri embarking on a spiritual journey, visiting the serene church presided over by the captivating Father Andrea. So-jin, plagued by foreboding, tags along, her heart heavy with the revelation that Yeon-u possesses an unprecedented level of the infamous cheating gene. Fearful of reliving past heartaches, she seeks solace in A-ri's words, who gently urges her to embrace her destiny of being drawn to such men.
Within the hospital walls, Yeon-u's attention is diverted from an unclaimed flowerpot gifted by an anonymous hand, to an innocent infant abandoned by its mother at birth. Father Andrea stands as a beacon of hope, nurturing the child and the family, but time is running out; if the mother fails to appear within the week, the baby's fate will be entrusted to the tender care of a child welfare system.
As the day wears on, Yeon-u's curiosity swells regarding So-jin's sudden silence, eagerly awaiting news of the test results. Her visit to deliver a lecture on egg freezing only serves to deepen the mystery, as she and A-ri conspicuously avoid discussing the topic with him. The duo finds themselves intrigued by the hospital's female populace, Yeon-u's flirtatious past catching up with him as they seemingly take a dislike to So-jin's presence.
Elsewhere, Sung-mi's heart skips a beat as she confides in Jung-tam about her menstrual irregularities. His words, painting her as the coolest woman he's ever encountered, resonate deeply, filling her with joy and validation. For the first time, she feels seen and supported as a woman.
Meanwhile, Mi-eun's thoughts are consumed by Gang-hun, her obsession leading her to share a meal with Yeon-u and later venturing to Gang-hun's father's restaurant. Despite her overt flirtations, Gang-hun remains oblivious to her charms, leaving Yeon-u to quip that Mi-eun's seductive prowess holds no sway over him.
And then, the unexpected twist: A-ri's DNA lover may be closer than she thinks—literally standing on the pulpit, as she finds herself inexplicably drawn to Father Andrea as he chivalrously fetches her beloved potato skewers from a bustling food truck. The stage is set for a romantic entanglement that defies all logic and convention.
As So-jin pondered the delicate matter of informing Yeon-u about the results of their DNA tests, fate intervened, leading her to stumble upon Yeon-u's mother at the research center. The woman struggled valiantly to maintain her slender figure, driven by an unspoken competition with her husband's mistress. So-jin, unaware of the woman's connection to Yeon-u, cautiously warned against the perils of undereating, yet her words seemed to bounce off an indifferent ear.
Elsewhere, Yeon-u's disappointment in his father's infidelities deepened. He sought to confront his dad, only to be met with a callous justification: one cannot remain with a woman they do not love. But the question lingered—how many hearts would his father claim to cherish in a lifetime?
On her way back, So-jin's path crossed with Sang-min, embroiled in an argument with a new woman. It seemed the man who had abandoned her was now engaged in a twisted game of triple deception. The revelation enraged the new paramour, who stormed off, leaving Sang-min vowing vengeance against So-jin.
Spurred by this encounter, So-jin impulsively messaged Yeon-u, branding him with the 'cheating gene.' She counseled meditation and temple visits, yet her words were heavy with judgment. When they met, Yeon-u felt affronted by So-jin's insistence that their relationship was doomed by his genetic makeup. He protested his innocence, urging her to know him better, but So-jin remained steadfast in her belief that DNA held the truth. Frustrated, Yeon-u retorted that he, too, had no interest in someone so quick to condemn.
Following this tense exchange, Yeon-u sought solace in a bar, where serendipity brought him face-to-face with Mi-eun, despite her being out with another. She chose to forsake her date and comfort Yeon-u, astonished by his distress over So-jin. Meanwhile, Gang-hun attempted to lift So-jin's spirits, reminding her that DNA tests were not destiny's blueprint. As he gently assisted her down from a perch, they stumbled into each other, and So-jin noticed the floral scent emanating from him, a moment he brushed off, labeling her a pervert with a smile.
Later in the evening's shadows, as So-jin discards the documents pertaining to Yeon-u, a pivotal detail dawns on her—Yeon-u possesses the healing gene, a glimmer of hope shimmering in the darkness for him. His inherent optimism, a beacon she cherishes, holds the promise of alleviating her burdensome depression. The very thought of him healing her soul is a soothing balm.
The dawn brings a new day, where Yeon-u meets with his latest patient, Ms. Heo, gently reminding her of their upcoming appointment. Ms. Heo, a model of patient compliance, even expresses her desire to honor Yeon-u's childhood nickname by bestowing it upon her unborn child.
Meanwhile, So-jin's senses are pricked as she senses a lurking presence. Gang-hun's voice, laced with concern, echoes in her ear, urging caution and the constant companionship of her safety alarm. He extends an invitation to share a meal at a cozy restaurant, where Yeon-u unexpectedly joins them, the two engaging in a silent dance of avoidance that piques Gang-hun's curiosity. Over a swift repast, Gang-hun's solicitousness towards So-jin is palpable, prompting Yeon-u's abrupt departure following a received message. So-jin, intent on an apology, is taken aback by his sudden exit.
The subsequent day finds Yeon-u reunited with his mother, who divulges the latest heartache—his father's involvement with a mistress, younger even than Yeon-u himself. Her anger simmers, yet her resolve to stay by her husband's side remains unshaken. Yeon-u's efforts to counsel and support her, even introducing her to legal aid, seem futile as she clings to the hope that her husband will return. This steadfast devotion, rooted solely in love for her husband, fuels Yeon-u's frustration and helplessness.
Following this emotional encounter, Yeon-u converges with Ms. Heo, their journey leading to the research center for prenatal tests. As So-jin conducts the DNA analysis, a somber revelation surfaces—the baby is at risk of developing Retinitis Pigmentosa, threatening its vision. In this vulnerable moment, Ms. Heo unmasks a surprising truth—she and Yeon-u's father are romantically involved. To Yeon-u, this is no novelty, having already been briefed by his mother. He warns Ms. Heo of his father's unreliability, fearing for her heart's safety, but she retorts with accusations of jealousy and paranoia, convinced he fears her child's potential to inherit the hospital's reins.
Ms. Heo abruptly storms out of the meeting, her exit a stormy departure, leaving Yeon-u to implore So-jin to maintain the utmost confidentiality of their discussion. He entreats her to keep in mind that his involvement in the case might be mere coincidence, a plea rooted in his desire to avoid the pitfalls of his father's past.
So-jin, struck by a pang of guilt, realizes the weight of her words and their potential to wound Yeon-u deeply. Seeking absolution, she trails after him, umbrella in hand—a forgotten symbol of their fleeting encounter. However, her apology meets with a brusque reception, Yeon-u admonishing her to look beyond the limitations of mere DNA tests and to comprehend the intricacies of human connections.
As night falls, Yeon-u is plagued by doubts, wondering if his harshness towards So-jin was justified. Meanwhile, So-jin's walk home is marred by a sinister presence lurking in the shadows. Desperate, she triggers her alarm, but Gang-hun, engrossed in his work, fails to heed the urgent calls. With her heart pounding, she takes to her heels, her voice urgent as she tries to reach him, until finally, his voice crackles through the line. By the time he arrives, breathless and anxious, he finds Yeon-u by So-jin's side, having caught her as she stumbled.
Yeon-u remains steadfast, guarding So-jin while Gang-hun gives chase to the perpetrator. Little wonder then, that the stalker reveals himself to be Sang-min, thirsting for revenge.
The episode draws to a close with So-jin expressing her gratitude to Yeon-u, her voice laced with apology. She pleads with him to allow further tests, for she has uncovered a remarkable truth—he possesses the healing gene. But Yeon-u is exasperated, arguing that understanding each other should transcend such scientific methods. In a moment of raw emotion, he leans in, his lips brushing hers, declaring that this is how an attraction test is truly conducted.
