Hee-Do and Yi-Jin's Relationship Timeline Will Make You Root For Them Even Harder

Hee-Do's diary picks up in the summer of 1998. After the IMF crisis causes Hee-Do's fencing club to shut down due to underfunding, she asks her mother, Shin Jae-Kyung, if she can transfer to Tae Yang High School, where her fencing idol Ko Yu-Rim is also a student. Jae-Kyung tells Hee-Do to give up fencing, which leads to an argument between them.

As Hee-Do storms out of her house, she meets the new paperboy in her neighborhood named Yi-Jin (a former chaebol who is forced to pick up part-time jobs after his family went bankrupt due to the IMF crisis). Hee-Do yells at Yi-Jin for throwing the paper directly at her peeing boy statue, which causes it to break. The two fight, but before they part ways, Hee-Do admits she yelled because she was angry at her mother. Talk about a memorable first meeting, right?

Yi-Jin also gets a part-time job at a DVD/comic book store. Hee-Do turns out to be a regular customer there, so the two meet once again. They have another run-in shortly afterward when Hee-Do goes to a club as a minor in hopes she gets arrested and be forced to transfer to Tae Yang High School. Unfortunately for Hee-Do, she enters a private room where Yi-Jin is hanging out with his friends. Sensing Hee-Do (and his friends) are up to no good, he makes Hee-Do leave the club with him. He scolds her for putting herself in a potentially dangerous situation, and that's when she confesses her plan to get transferred. Later that night, Yi-Jin also opens up to Hee-Do about his family going bankrupt, and their encounter ends with the two formally introducing themselves.

Eventually, Hee-Do is able to transfer to Tae Yang High School after begging the school's fencing coach to put her on the team. She tells Yi-Jin the good news, and from then on, she spends her days training and trying to achieve her dream of becoming Yu-Rim's rival.

One day, while Hee-Do goes to visit Yi-Jin at his apartment, she sees two men yelling at Yi-Jin. They used to work at his father's company, but after it bankrupt, the men were laid off and unable to support their families. Since they couldn't get in touch with Yi-Jin's father, they took out their frustrations on him instead. After Yi-Jin promises he'll never be happy again and will spend his entire life thinking of the pain his father has caused, Hee-Do tries to comfort Yi-Jin by getting ice cream together at the supermarket. That's when the two open up to each other about their dreams. Hee-Do then takes Yi-Jin to the water fountains at her old school, and after seeing Yi-Jin smile, Hee-Do tells him to be happy whenever they hang out together.

Hee-Do and Yi-Jin continue spending time together. One night, Yi-Jin visits Hee-Do at the gym while she's training to join the national fencing team. The two spar and Yi-Jin gives Hee-Do a pep talk. He tells her he knows she'll do well during tryouts, and when Hee-Do asks Yi-Jin why he roots for her when her own mother doesn't, he says, "Because you give me hope, and I want more from you." During their walk home, Hee-Do tells Yi-Jin, "Let's become great together." She then gives him one of her swords, which shows how close the two have gotten.

Hee-Do eventually makes it onto the national fencing team. She wants to tell Yi-Jin the good news, but discovers he quit both of his part-time jobs and moved away to get away from the pressure of his dad's business failures in Seoul. When she returns home, Hee-Do sees Yi-Jin returned her sword and had written a message on it that reads, "National Team Member Na Hee-Do," which confirms he heard about her joining the team. Although Hee-Do is upset Yi-Jin left without saying goodbye, she trusts he made the right decision.

After Yi-Jin's departure, he and Hee-Do continue on with their lives. Despite them being apart, the pair's bond grows stronger even in absence as Hee-Do uses old recordings of Yi-Jin to inspire her during tough times. Similarly, Yi-Jin repeats a voicemail from Hee-Do whenever he needs some words of encouragement. Hee-Do goes on to win another fencing competition, while Yi-Jin decides to stop running away and moves back to Seoul to become a journalist.

Five months after Yi-Jin moves to Seoul (and six months since he's seen Hee-Do), he becomes a trainee reporter and gets assigned to cover the Asian Games. Since Hee-Do is competing in the event, the two finally reunite. Hee-Do invites Yi-Jin to get lunch with her, and he finds out Hee-Do has a boyfriend named Jung Ho-Jin, who Hee-Do has been dating for only three days. The couple is very lovey-dovey during their meal, and Yi-Jin ends up teasing Hee-Do about it. He doesn't appear jealous, just amused. Hee-Do and Ho-Jin then break up two weeks later.

When Hee-Do and her online friend (who is Yu-Rim, unbeknownst to her) agree to meet in person for the first time, they agree to meet at the park with a yellow rose in hand. Worried that whoever Yu-Rim is about to meet is a predator, Yi-Jin accompanies her to go meet Hee-Do. But when Yu-Rim realizes her online friend is Hee-Do, afraid to reveal her identity, she panics and gives the yellow rose to Yi-Jin.

When Hee-Do sees Yi-Jin with the rose, Hee-Do tells him, "I have to have you." Yi-Jin says he's not the person Hee-Do was looking for, which causes her to become flustered and run away embarrassed. Hee-Do ignores Yi-Jin for the next few days and eventually confesses she doesn't know exactly how to feel about him. Later, she compares her relationship with Yi-Jin to a rainbow.

Yi-Jin becomes even more protective of Hee-Do as the months go by, and when she's injured while filming a documentary, he doesn't think twice about picking her up in front of all his colleagues in order to take her to see a doctor. During their drive, a rainbow suddenly appears, leading Hee-Do to tell Yi-Jin to stop the car, so they can appreciate the view together. When Hee-Do asks Yi-Jin which word he would pick to describe their relationship, he says, "Love . . . I love you, Hee-Do." While Yi-Jin's love still seems to be platonic at this point, Hee-Do still feels moved. Still, she admits her feelings toward Yi-Jin aren't as strong, which Yi-Jin is OK with.

That all changes by New Year's Eve. Hee-Do, Yu-Rim, Ji-woong, and Seung-wan all went to Yi-Jin's apartment to celebrate the holiday, but after hearing rumors about the start of the new millennium being the end of the world, everyone leaves to go see their families. Hee-Do stays with Yi-Jin and then kisses him at the stroke of midnight.

Fearing his career as a sports journalist will come into conflict with Hee-Do's as a fencer and he could hurt her, Yi-Jin chooses to keep his distance from Hee-Do, telling her he only sees her as a friend. But later, he becomes noticeably jealous of one of Hee-Do's fencing friends, Jun-Ho, tipping Hee-Do off to the fact that Yi-Jin may not be being truthful about his feelings. Later, after finding out about how Jae-Kyunk betrayed Hee-Do's fencing coach in the past, Yi-Jin tells Hee-Do they should stop seeing each other and keep their distance. Hee-Do says she's willing to risk everything to stay by Yi-Jin's side, even if it's just as a friend. That's when Yi-Jin is overcome with emotion and kisses her. Yi-Jin agrees to give dating a try.

So, the big question is, do Yi-Jin and Hee-Do last as a couple? At the end of episode fourteen, Hee-Do's daughter in the present day, Min-Chae, watches an interview between the pair on YouTube, and Yi-Jin and Hee-Do appear to talk as if they haven't seen each other in years. During their chat, Yi-Jin also congratulates Hee-Do on her recent wedding. Does this mean they break up because their jobs pushed them apart? Not necessarily. Some fans are convinced the two get married and hide their relationship from the public.

To see how Yi-Jin and Hee-Do's love story ends, make sure to watch the last two episodes of "Twenty-Five Twenty-One" on Saturday, April 2, and Sunday, April 3.