Episode 1 of "Positively Yours" begins with Hui-won taking a pregnancy test and receiving a positive result. The story then flashes back to four weeks ago, when Hui-won attended an elite dating event on behalf of her friend. In the survey answers, Hui-won wrote that she had no intention of getting married. While there, she spotted her boss, Soon Hee. To avoid an embarrassing encounter, Hui-won approached Du-jun, who was only there to entertain his mother's nagging behavior. Like Hui-won, he had no plans to get married. He came along with his secretary, Mr. Go, but unfortunately, Secretary Go ran to the toilet, leaving Du-jun alone. This is when Hui-won pounced and tried to get him to play a couple. He turned her down, and she slipped while getting him drinks. In the end, Hui-won ended up embarrassing herself. Du-jun left shortly after and vented to Secretary Go on his way home.
The next day, Hui-won vented to her friend, Mi-ran. Through a flashback, we learn that Hui-won has dated before but is a bit conservative. As they drank, Mi-ran encouraged her to find some well-deserved romance in her life. Meanwhile, Du-jun's parents learned that the dating event didn't go well. They questioned if Du-jun's sister-in-law, Jeong-eum, was involved. She has quite the temper, and it's possible that she blames Du-jun for her husband's death. Unfortunately, Du-jun and his brother were on a rock climbing trip when an accident occurred, and his brother fell from a cliff.
At Hui-won's office, her colleagues heap praise upon her diligent work, speculating that she'll be chosen for a study trip to Germany. Meanwhile, Soon-hee views Hui-won's efficiency as a threat and relentlessly urges her to excel further. This time, she finds fault in Hui-won's intern, Se-hyun, and orders Hui-won to devise a new plan to boost beer sales by the next meeting.
Hui-won storms out in a fury and calls her friend, Min-wook, who unexpectedly shows up to comfort her. Their conversation drifts to Hui-won's aversion towards marriage. A flashback reveals that Hui-won has had a crush on Min-wook since school days, and it seems he feels the same, wanting Hui-won to find happiness. However, Hui-won can't shake off the trauma of her parents' divorce.
Du-jun continues to work diligently for the family company, known for his cold and ruthless demeanor, prioritizing diligence over loyalty. His father supports him but asks him to take over another family company, Taehan Liquor, which happens to be the same company where Hui-won works.
After a long day, Se-hyun and Hui-won coincidentally meet at a pub. Se-hyun reveals she's dating an older man and asks about Hui-won's love life. As she heads home, Hui-won reflects on Se-hyun's question and begins to question if Min-wook is the one for her. She buys him some tteokbokki and heads to his place. She's shocked to see Mi-ran and Min-wook kissing outside his apartment.
Hurt, she heads home crying. It starts raining, and she takes shelter at the nearest bus stop. Du-jun passes by in his car and accidentally splashes water on her. She overreacts and bangs on his window. Du-jun fails to recognize her and hands her a cheque before driving off.
In the privacy of his home, Du-jun confides to Secretary Go that he's about to take over Taehan Liquor. The following evening, Hui-won attends a beer launch party for research, where she unexpectedly runs into Du-jun again. This time, he recognizes her as the woman from the dating event. Initially shocked when she approaches him, he calms down as she helps him learn how to best enjoy his beer.
With Secretary Go in the toilet again, the two drink and talk as Hui-won teaches him how to mix beverages and pair them with snacks. She encourages him to play a basketball match game and win her a homebrew beer maker and a doll. Unfortunately, the other team cheats, so they resort to stealing the prize. After stealing the prize, Du-jun and Hui-won run off until they're sure no one is following them. They belatedly realize that they stole the doll and not the homebrew beer-making machine. Still, they have a great time, drinking by the Han River.
Hui-won shares her dream of traveling to Germany and eventually making her own beer. Du-jun insists he has no dreams. As they talk and drink, they end up kissing.Somehow, they make it to a hotel and spend a steamy night together.
The next morning, Hui-won wakes up and regrets what happened. She's more frustrated when she spots a necklace in Du-jun's belongings. She assumes he's either married or in a relationship and leaves behind the cheque he once wrote for her, walking away without recognizing Du-jun as the man who gave it to her in the first place.
Elsewhere, Jeong-eum causes a scene at the museum when one of her artists chooses to become someone else's plaything. Back at the hotel, Du-jun wakes up after sleeping well for the first time in a while. On his way out, he runs into Jeong-eum, who immediately asks her secretary to look into the woman Du-jun was with. She also asks him whether he's planning to get married. Given her tone, she clearly doesn't want Du-jun to be happy. A flashback from her husband's funeral proves that she blames Du-jun for what happened.
Over the next few weeks, Hui-won continues to excel at work, while Du-jun grows distracted, thinking about her constantly. As the days pass, Hui-won starts feeling nauseous and tired. She drops by the chemist's and after explaining her symptoms, the doctor advises her to take a pregnancy test.
Hui-won immediately heads home and takes a few pregnancy tests, which come back positive. She's shocked as doctors had initially told her that she has health issues and pregnancy might not be in her future.
Mi-ran walks in on her friend, processing the news. She spots the pregnancy test and realizes that her friend is pregnant. Excited, she takes her to the gynaecologist to confirm. It turns out she's really pregnant.
Mi-ran asks about the father, but Hui-won never got Du-jun's name or number. Just then, Se-hyun walks in with Du-jun. Immediately, Hui-won assumes he is Se-hyun's boyfriend and loses her cool. She walks over to him and grabs his collar as she heavily scolds him. As things heat up, Se-hyun announces that Du-jun is her uncle. Simultaneously, the nurse calls out for Hui-won, reminding her she forgot her first ultrasound. At this point, Du-jun realizes that Hui-won is pregnant.
The scene becomes even more intense as everyone tries to process the news and the emotions that come with it. The tension between Hui-won and Du-jun is palpable, while Se-hyun looks on in shock and confusion. The nurse's reminder of the ultrasound adds a sense of urgency to the situation, making it clear that this is a significant moment for Hui-won and her unborn child.
