In the first scene of XO, Kitty E3, Dae is debating whether or not to sign a Non-Disclosure Agreement (NDA) for the father of Yuri. Sung-jin had requested Dae to sign the NDA to protect his daughter. He does this because he thought Dae and Yuri were a real couple. Dae's father is concerned about the gravity of the situation. This comes as a result of Dae's online success, but his sister is excited about the relationship.

See Also: XO, Kitty — Episode 2 Recap

Dae admits to them that he worries if Kitty finds out about his financial situation, she won’t want to stay with him. However, Q and Minho bring Dae to class, which ends their conversation. Dae promises to give Kitty a detailed explanation later. Yuri texts Juliana in the interim to let her know how much she misses her. In a flashback, it shows that Yuri's maid catches them in an inappropriate situation.

In the present, photographers swarm the area outside K.I.S.S. in an effort to snap photographs of Yuri and Dae together. Dae presents the contract to Yuri while holding hands and acting as a couple. Dae requests permission from Yuri to tell Kitty that their relationship was a lie. He is cautioned by Yuri about the possible repercussions of the knowledge going public, but she also admits that she was dating Juliana and attempting to hide it from Juliana's parents.

Yuri breaks down from missing her girlfriend, and Dae gives her a piggyback ride to help her escape the cameras. Unbeknownst to them, Kitty sees them together and believes Dae is in a relationship with Yuri. Kitty battles the nickname "Portland Stalker" given to her by her classmates at school but attempts to ignore them.

Yuri gives Dae her vacation schoolwork to complete, so he leaves the essay with her. Dae says he can't wait to leave their fictitious romance. Juliana suddenly enters the school and informs Yuri that she is caught and is moving. Although Juliana encourages Yuri to stay at K.I.S.S. for the rest of the year and makes a commitment to soon return, Yuri expresses her regret.

In the janitor's room, the two girls share a passionate moment before Yuri leaves for class. Jin learns from Professor Lee that Yuri asks Dae to compose her summer homework essay. Jina, who supports her daughter, requests Professor Lee to provide evidence that Dae did, in fact, write the article for Yuri. Professor Alex helps Kitty find her class and runs into Professor Lee, whose abrupt demeanor perplexes him. Kitty becomes even more enraged when she sees Yuri and Dae seated together in class.

Professor Lee tells Kitty after class that tutoring is necessary because she is falling behind academically. Kitty is a target by other cliques during lunch, which forces her to sit with Q. She confides in Q that she thinks Dae's romance with Yuri is a deception. Kitty wants to force Dae to admit his genuine feelings after becoming convinced that he dislikes being around Yuri. While Florian, a French EXPAT student, diverts Q's attention, Kitty decides to arrange for the two of them to go on a date.

When Jina calls Yuri into her office, Jina questions her about cheating on her summer schoolwork. Yuri strikes a deal with her mother, promising to behave well in return for being able to go to an Icelandic DJ festival. After lunch, Kitty finally makes it to her Chemistry class where she sees Minho sitting next to her. After a disagreement, Kitty openly admits that Minho was once featured in a diaper commercial as a young child. Professor Alex decides to let students switch lab partners after Minho, embarrassed, draws jeers from the class. Florian is persuaded to join Q by Kitty.

Following class, Kitty visits the library where she meets Dae, who will serve as her tutor. Kitty discovers pictures of her mother while researching and hopes to locate where her mother would fit in at the school. When Eunice tells Yuri about Kitty's reveal of Minho's secret, Yuri is perplexed as to how Kitty came by such sensitive knowledge. Eunice attributes the leak to Dae. Yuri arrives at the library to disrupt Dae and Kitty's tutoring session.

She shows there just as Dae is about to admit the truth about his relationship with Yuri when Kitty tells him that the entire school knows about Minho’s secret. Yuri discreetly cautions Dae about the NDA before leaving. Dae makes the decision to break up with Kitty and inform her of his genuine relationship with Yuri. Kitty is in the library alone after he gives her necklace back.

Q tells Kitty that evening that Florian has followed him on social media, proving that her matchmaking strategy was successful. Kitty is in shock to learn that her mother, Eve, had a kid in South Korea in 1993, several years before Kitty was born, when a hospital tag from her mother's photobook slips out in the midst of the excitement - which marks the closing of the episode.

XO, Kitty is now streaming on Netflix.