The seventh episode of Dear X commences with the camera lens of Lim Hee-kook, Le-na's cousin and a reporter, capturing Ah-jin and In-gang in an intimate embrace. Meanwhile, Le-na and Jun-seo exit a bar where Jun-seo engaged in a physical altercation with three men who were disparaging Ah-jin. The reporter's images make their way to Mi-ri, who warns Ah-jin that a romantic scandal could jeopardize her career. Ah-jin assures her that this is not a fleeting affair and convinces Mi-ri to allow her to speak directly to the reporter. Ah-jin then meets with Lim and persuades him to work for her instead of Le-na. She offers him exclusive stories about her relationship with In-gang and even promises to provide photographs for each scoop.
As expected, the news about their relationship breaks with a more positive than negative reception. However, Ah-jin's vengeance against Le-na is not yet complete. She manipulates Jae-oh into going on a date with Hyang-i, where he secretly records her discussing Le-na's DUI offense, which Le-na ultimately took the fall for. Just after Mi-ri advises Le-na to take a break from work, Ah-jin releases the video online, effectively banning her from the industry for good.
We then witness a montage of Ah-jin and In-gang spending time together as a blissful couple over the next several months. Approximately a year later, Jun-seo remains in contact with Le-na for reasons unknown. She persuades him to attend the premiere of Ah-jin's movie. While there, Jun-seo recalls Ah-jin's statement that she would only date In-gang for a year.
Upon returning home, Jun-seo finds Jae-oh waiting for him. Both have not heard from Ah-jin in a while. Ji-sun calls Jun-seo requesting more money, but he ignores her call. His grandfather is now gravely ill, and Jun-seo orders the servants not to let Ji-sun near him. Of course, this doesn't deter Ji-sun, who breaks into her son's house and discovers he has invested in Longstar Entertainment. She confronts Ah-jin about this but is reminded by the latter that she still hasn't told Jun-seo about his parentage. This keeps Ji-sun quiet for the moment.
One day, Sung-hee - Ah-jin's archrival from school - sees her and publishes an online post about Ah-jin's behavior in school. It causes a scandal but is ultimately called out by Jae-oh and others from the school for being a hypocrite. The post is subsequently deleted.
That night, In-gang is away and Ah-jin struggles to sleep. In-gang's grandmother, Hong Kyung-suk, learns she is ill and comes over to take care of her. Surprisingly, Kyung-suk tells her that she accepts Ah-jin, even if everything in the article is true.
During his travels, In-gang finds himself attending various promotional events, all while Mi-ri urges him to not delay accepting his next project. He hints at his desire to marry Ah-jin and start a family with her. Meanwhile, Choi Jung-ho, the coffee shop owner Ah-jin got arrested from, has been released from jail and approaches her to let her know. He also greets Kyung-suk, who he met while volunteering at the prison. At Jun-seo's house, Jae-oh and Le-na bump into each other, and as he is about to leave, he receives a call from Ah-jin. Jun-seo arrives home at that moment and realizes that Ah-jin has reached out to Jae-oh.
Mi-ri meets Jun-seo, now the CEO of Crowndium Pictures and a secret investor of Longstar Entertainment. His new book is being adapted for the screen, and his contract with Mi-ri stipulates that they must cast Ah-jin in the lead role. Ah-jin and In-gang discuss the opportunity, and In-gang suggests they think about it for a week. That night, Jun-seo finds Ah-jin waiting for him at home, knowing he pulled the stunt with the contract to get her attention. She reminds him of her promise to break up with In-gang in a year and accuses him of cozying up with her enemy, Le-na. Jun-seo assures her that he's keeping Le-na close to ensure she doesn't bother Ah-jin. Le-na arrives and is annoyed to see them together.
On Ah-jin's birthday, the couple goes on a date to a fancy restaurant. In-gang is about to ask her something when they are interrupted by Le-na and Jun-seo, who join them at their table. Le-na exposes Jun-seo and Ah-jin's relationship in front of In-gang and the fact that she recently met him.
In-gang excuses them from the table and asks Ah-jin for an explanation. She allays his doubts, but then he receives a phone call—Kyung-suk was making Ah-jin a birthday dinner at her house when she found her diary, the one Ah-jin stole. Now, she's back at her own apartment without having had dinner. Of course, all In-gang knows is that she found her lost diary.
With a rush for a flight, he asks Ah-jin to check on his grandmother. Ah-jin gets a ride from Jae-oh and goes to her house. Jun-seo arrives shortly after, and in the next few minutes, they hear a loud thud. Ah-jin is standing at the top of a flight of stairs. Below, Kyung-suk has fallen down and seems to be dead.
