The eighth episode of Dear X commences with Kyung-suk's hospital bed, where In-gang rushes in with frantic steps. Ah-jin bows her head in prayer, and Jun-seo muses on whether her prayers are for Kyung-suk's survival or her own guilt. Ultimately, the old woman's spirit passes on. At the funeral, Ah-jin offers her support to In-gang, telling the police that Kyung-suk had been feeding the stray cats when she suddenly felt dizzy and fell down the stairs. Flashbacks hint at Kyung-suk's accusations against Ah-jin for ruining her grandson's life.
Choi Jung-ho makes a sudden appearance, and In-mo, In-gang's brother, confronts him about his involvement in Ah-jin's father's death. Jung-ho insists that Ah-jin is innocent, explaining that his time in prison allowed him to reflect on Ah-jin's situation and how differently her life might have turned out if there had been a responsible adult in her life. He pities her and genuinely wishes her the best.
Reporter Lim calls Ah-jin, hoping to get a scoop from her, but she cuts the call abruptly. He then tries to get something from Sung-hee, but she shuts him down as well. It turns out that Jae-oh has threatened to expose her own secrets from school at her workplace to keep her quiet.
During the old woman's memorial, Ah-jin crosses paths with Director Seol Yeong-uk, who takes a liking to her and offers her a role in his movie. His movies tend to gain a global platform, and Mi-ri thinks this will be a great opportunity for Ah-jin.
Meanwhile, Jun-seo has been torn between the question of whether Ah-jin killed Kyung-suk or not. He meets her in a parking lot and asks for the truth, but she teases him, asking him what he would do if she had really done it.
At her grandmother's cozy apartment, In-gang's encounter with a neighbor sets the stage for a twist in the narrative. The neighbor, overheard by In-gang, whispers that Kyung-suk was embroiled in a heated altercation with another woman, accusing her of deception. She further reveals that a fellow resident on the same floor has an undercover security camera that may have captured the altercation. In-gang pursues this lead and speaks with the resident, who sadly informs him that the footage is in the hands of the police.
Elsewhere, Jae-oh receives the same footage from the police, only to find Jun-seo waiting at a bar, her eyes eager for the truth. Jae-oh, though, is resentful at being tasked with this mission, his faith in Ah-jin's innocence still intact. As if to emphasize this tension, a rumor emerges about In-gang purchasing a ring for Ah-jin. This news bothers Director Seol, who cautions Ah-jin that it could tarnish the experience of their film. She leaves the meeting hastily, her mind in turmoil.
Mi-ri, who has become an unofficial confidante to both Ah-jin and In-gang, mentions that In-gang is planning to retire soon. She then turns her attention to Ah-jin, asking if she truly desires to marry In-gang. Ah-jin, with a heart as cold as steel, responds that she intends to break up with him.
Meanwhile, Jun-seo remains reluctant to watch the video. Le-na intervenes, dragging an inebriated Jun-seo home where Jae-oh is cooking a meal. The night continues to spiral out of control as Ah-jin meets In-gang at his house and delivers a harsh blow by breaking up with him while revealing her cruel side and stealing his grandmother's diary. She reveals that the old woman has discovered the truth. In-gang questions her about what she did to his grandmother, and Ah-jin simply replies that she told her the truth.
Ah-jin then leaves and calls Reporter Lim, instructing him to prepare an article about her breakup with In-gang. She then reaches out to Jae-oh and when he arrives, he notices a car following Ah-jin and urges her not to stop. Instead, he blocks the car's path and demands to know who it is. A group of men emerges and Jae-oh is knocked unconscious. He later wakes up on the street and receives a call from Ah-jin, but he lies to her and says the car was just paparazzi.
Mi-ri pays a visit to In-gang's house to lend him support and tells him that she won't be renewing Ah-jin's contract. They spend time together drinking before she returns the next day to give him some food. However, she finds him in the bathtub with a slit wrist - he has taken his own life.
Jae-oh finds himself admitted to the hospital, nursing his wounds, while Jun-seo pays him a visit. As Jae-oh recalls the cross tattoo on the assailant's arm, he keeps his suspicions to himself, choosing not to divulge them to Jun-seo. It is then that the news of In-gang's suicide shocks the nation.
Jun-seo storms into Ah-jin's home, accusing her of tearing apart a family and lacking humanity. She offers him the choice to leave if he so desires, without blame.
In-gang's funeral takes place amidst a sea of mourning. Meanwhile, Ah-jin retires to her apartment, sitting by the bathtub, begging for In-gang's understanding. This act ignites a frenzy among the fans, who protest the entertainment company and chase Ah-jin with eggs. Surprisingly, Sung-hee steps in to protect Ah-jin from the eggs, guiding her back to her apartment. Sung-hee makes some comments about Ah-jin's payment and then leaves with some of her belongings.
Even Mi-ri, once a supporter of Ah-jin's, now meets with Reporter Lim, urging him to join forces with her to expose Ah-jin's father's case and bring her down.
Back at Ah-jin's apartment, Ji-sun comes by and kneels before her, apologizing for everything. Ah-jin refuses to accept it, but as Ji-sun rises, she tells Ah-jin to convey her apology to Jun-seo. Suddenly, Ah-jin starts laughing maniacally.
A flashback takes us back to the scene between Ah-jin and Kyung-suk. Ah-jin admits to using the diary but insists she genuinely cares for In-gang and Kyung-suk. Kyung-suk says she still considers Ah-jin a part of her family and hugs her, telling her not to do it again. She even agrees to keep the whole incident a secret.
In the present, as Ah-jin tells Ji-sun that she hated her the most when Ji-sun showed her kindness, she explains that those moments made her fear she would actually care for Ji-sun. She laments that hope is a luxury she cannot afford.
In the flashback, Kyung-suk goes out to feed the kittens in the building. She calls out to Ah-jin to join her but suddenly experiences dizziness and falls down the stairs as Ah-jin reaches out to catch her. Back in his apartment, Jun-seo sees the video and realizes the truth.
The episode ends with an introduction of a new character: a powerful man who had seen Ah-jin from his car while she was crossing the street. It was his men who brutally beat up Jae-oh. Now, he orders his men to find out how Ah-jin is connected to Jae-oh and Jun-seo.
