Episode 1 begins with a scene at a school. A young Son Hae-yeong asks her PT teacher why the girls have to play dodgeball while the boys play soccer (hence, taking up more space on the field). As she argues with her teacher, we learn that Hae-yeong’s mother was very generous and kind.
So, she kept fostering other kids in their house. Hae-yeong felt like she lost out on the time, energy and love her mother would spend on those kids. This is how she came to think so much about profit and loss, even in her personal life.
At present, a grown-up Hae-yeong is at a colleague’s wedding. She and another colleague wonder how much money they should give as a wedding gift. Hae-yeong laments how much she’s spent on such weddings in general. In fact, the groom turns out to be none other than Hae-yeong’s ex-boyfriend, Woo-jae, who she broke up with just six months ago.
Elsewhere, a man named Kim Ji-uk attends a job interview at Liter Electronics. Instead of his qualifications, Ji-uk is questioned about being an orphan. The woman next to him is then grilled about a hypothetical scenario of sexual harassment. Ji-uk steps in and says the matter should directly go to the Human Rights Commission. This doesn’t go down well with the interviewers and later, Ji-uk apologizes to his fellow interviewees as well.
While at the wedding, Hae-yeong gets a call from her mother who seems to be in a nursing home. The nurse tells Hae-yeong to visit soon. As the wedding goes on, a flashback shows Hae-yeong’s breakup with Woo-jae. She curtly tells him that she doesn’t love him anymore.
He’s heartbroken and falls over, prompting Hae-yeong to stick a bandage on his hand after he injures himself. At present, the wedding shows pictures of Woo-jae and his wife Yi-lin’s engagement. The photos show the same bandage on Woo-jae’s hand.
When her colleague mentions this is the couple’s one-year anniversary, Hae-yeong realises he has been cheating on her for at least six months. Angrily, Hae-yeong pulls out a tablecloth and turns it into a makeshift wedding dress, using a napkin as a veil. She confronts him about the cheating in front of everyone.
The scene shifts to an apartment where a young web novel writer named Ja-yeon is trying to write an erotic scene. She’s then joined by another woman named Hui-seong. Both of them seem to be Hae-yeong’s friends. Hae-yeong herself arrives, looking morose. She shows them a bunch of flowers — she caught the wedding bouquet! Turns out, none of the above happened and Hae-yeong was polite throughout the whole wedding.
At present, she complains about spending all that money as a gift for her cheating ex. Her friends list how Hae-yeong always broke up with her boyfriends because she thought she was losing out on the deal. Whether it was to do with food, bills or even sex.
Meanwhile, Ji-uk returns the suit he wore to the interview to a policeman, who he knows very well. Apparently, Ji-uk is a do-gooder who has called in several crimes and helped the police catch criminals. He even helps the elderly and is known as an angel.
Back at home, Hae-yeong walks Hui-seong out. Hui-seong asks about visiting Hae-yeong’s mother, but Hae-yeong lies, saying her mother’s house is in disrepair. She then says she’s going to the nearby grocery store to buy her favourite jellies. They discuss how the store worker, none other than Ji-uk, seems to hate her. Indeed, when Hae-yeong goes to the store, she and Ji-uk get into an argument over discontinued jellies. It seems they’ve known, and disliked, each other for a while.
Back home, Ja-yeon finishes her chapter and gets several hate comments. But there is one person who writes a positive comment. That person turns out to be a rich woman named Jeong-a. Her son is Gyu-heon, the CEO of Kkulbee Education, the company where Hae-yeong works.
Gyu-heon’s father complains about Kkulbee being second in rank. He tells Gyu-heon to get the company to first place within a year. If he doesn’t, he has to get married. As a result, Gyu-heon comes to work in a foul mood. His secretary, Ha-jun, deals with his outburst while secretly wanting to transfer to a different department.
While passing by the store, Hae-yeong argues with Ji-uk again. After she leaves, Ji-uk gets a text from someone which seems to bother him. Maybe an ex-girlfriend?
At work, Hae-yeong and her colleague discuss all the benefits that married people get from the company. Later, Hae-yeong speaks to Woo-jae and confronts him about the cheating. He’s utterly remorseless. She demands he pay her money back but he refuses.
A flashback to six months ago shows Hae-yeong sitting outside a store with a drunk Woo-jae. Woo-jae is happy due to a promotion. In his drunk state, he says that she’s the only person on the hook for taking care of her mother. This made Hae-yeong feel like Woo-jae was losing out by being with her, as the sole caretaker of her mother. So she dumped him. Now, she’s determined to make him regret it.
She calls him and makes it clear that she’s meeting his wife, Yi-lin. Woo-jae rushes over to where the women are seated. But turns out, Hae-yeong didn’t say anything. She had actually made a candle stick out of the bouquet she grabbed in their wedding and was gifting it to them. She also wants to be friends with Yi lin. The scare is enough to put Woo-jae in his place. He then reveals that Yi-lin controls all their money and his allowance isn’t enough to pay her back. He begs her to let him pay when she gets married.
Meanwhile, Ha-jun and Gyu-hyeon have created a challenge for the employees to come up with an idea to boost the company’s success. Gyu-heon is happy but still refuses to give Ha-jun a transfer. Hae-yeong then sees the poster for the idea contest. The winners will join the president’s personal team to execute the idea as well as a fast-track promotion.
But her boss says that single women are never hired for the teams directly under the CEO. Apparently, due to Gyu-heon’s father’s reputation with single women, only married women are now given those positions.
Annoyed, Hae-yeong goes to the grocery store and buys alcohol. She drinks and fumes about how everything requires marriage. Sometime later, a drunk Hae-yeong goes up to Ji-uk and stares at him from across the counter before suddenly asking him to be her groom.
An epilogue shows Ji-uk sitting nearby while Woo-jae is talking to Hae-yeong about her mother. He overhears the conversation and later finds Hae-yeong. He sits by her and silently offers a cigarette.
