In XO, Kitty, Dae, played by Choi Min-young, has been dating Kitty for years, and when they finally get to be with each other, it is nothing like what either of them had imagined.
Dae and Kitty met at a romantic spot when she visited Seoul with her family. The two of them have been in a long-distance relationship ever since. They know everything about each other, even though they live miles apart.
Kitty decides to move to Seoul when she gets into KISS. She plans to surprise Dae at the welcome party, but it is Dae who has a bigger surprise for her.
The fake relationship
Before Kitty moved to Seoul, Dae made her believe that he comes from a rich family, but the truth is that Dae’s father is Yuri’s father’s chauffeur. Dae is one of the best students at KISS, but he has a hard time paying his tuition.
He decides to take Yuri’s offer, who needs a fake boyfriend to convince her parents that there is nothing between her and Juliana. In exchange for pretending to be her boyfriend for one night, Yuri pays his tuition.
Kitty was never supposed to see Dae and Yuri together, but she does. Kitty decides to go back home the next day, but Dae stops her. He tries to tell the truth, but he never gets to do that.
He is forced to pretend to be Yuri’s boyfriend for more than one night when Yuri’s father publicly accepts their relationship and makes Dae an intern at the Han Hotel to protect his own public image.
Dae cannot break up with Yuri because the Han internship allows him to help his family financially and give them the comforts that they had been denied for so long.
Their fake relationship goes on for longer than expected, and Dae wants to tell Kitty the truth, but Yuri forbids him from doing that, as she does not trust Kitty completely. Dae does not like hurting Kitty, but he has no choice in the matter.
The start of the relationship they desired
Although Kitty is led to believe that Dae and Yuri are truly together, Dae still wants to be her friend. However, even that does not work out well, as Yuri never gives Dae Kitty’s Chuseok present, making Kitty think that he does not care.
Dae is then forced to witness Kitty trying to avoid him and get over him at Min Ho’s party. Yuri decides to publicly break up with Dae when she finds out what her mother did to Juliana, and Dae finally gets to be with Kitty the way the two of them had imagined.
However, Kitty and Dae’s relationship is still not perfect by any means, as Dae cannot tell her the truth about his breakup with Yuri.
Dae and Yuri had become good friends when they were pretending to be a couple, and they continue being friends even after the arrangement is over. To help him out, Yuri tells Kitty the whole truth.
Kitty forgives Yuri and Dae, and Dae takes her on a date on the school trip and confesses that he loves her. His romantic gesture wins Kitty’s heart, who reciprocates his feelings.
Saying goodbye
Kitty had started developing feelings for Yuri, but since she is with Dae, she tries to ignore them. Those feelings do not go away with time, and at the end of the term talent show, Kitty finally tells Dae about them.
Additionally, when the exam results come out, Dae finds out that he has not ranked first, which means he will now lose his room and board scholarship.
Despite everything, when he finds out that Kitty left without saying goodbye and left her mother’s necklace for him, he races to the airport to mend their differences.
There, Kitty and Dae break up on good terms and say that they will always be each other’s first love. Kitty says goodbye to the boy for whom she had moved to Seoul and goes back to the US.