In the beginning of Perfect Family’s third episode, Soo-yeon hurries from Kyeong-ho’s residence to rendezvous with Sun-hui. She attempts to see her, but Eun-joo, Sun-hui’s mother, does not allow Soo-yeong to visit her friend. Soo-heon is determined to see Sun-hui and enters her bedroom to discover Sun-hui in a state of shock. Soo-yeon attempts to convince Sun-hui to accompany her to the police station and take responsibility for the murder instead.
She inquires if Sun-hui was responsible for setting fire to Kyeong-ho’s home and murdering his parents, but he remains silent. Soo-yeon removes her wig and attempts to manipulate Sun-hui into acknowledging her role in Kyeong-ho’s death in retaliation for the harm she suffered from the fire Sun-hui started. Soo-yeon attempts to bring Sun-hui along, but Jin-hyeok prevents Sun-hui from leaving. Soo-yeon becomes angry and decides to leave for home.
At the same time, Sun-hui has a breakdown in her room. While the other children discuss Kyeong-ho’s suspected drug problem, Soo-yeon decides to stay home from school. Hyun-woo attempts to protect his friend and warns to harm his classmate who talks negatively about Kyeong-ho. Soo-yeon considers going to the police station and remembers the event at Kyeong-ho’s place that resulted in his death.
A scene from the past reveals that Soo-yeon becomes upset when Kyeong-ho informs her that he plans to ask Sun-hui out. She attempts to prevent him from doing it, yet becomes frustrated when Kyeong-ho misinterprets her sexual orientation. She is unable to admit her real emotions for him and chooses to spoil his unexpected plan.
Soo-yeon shows Kyeong-ho the swan keychain and explains that Sun-hui had handed it to her because she did not have feelings for him. Kyeong-ho requests Soo-yeon to give him the keychain, leading to a fight between the two. Soo-yeon becomes angry and begins wrecking the painting and the cake. The confrontation results in Soo-yeon’s wig coming off. She feels ashamed and questions why she always has to endure this pain.
Kyeong-ho attempts to intervene as she grabs a knife to commit suicide. Simultaneously, Sun-hui hears the commotion outdoors and goes inside, discovering Soo-yeon pointing a knife at Kyeong-ho. When Sun-hui attempts to step in, Soo-yeon becomes angry and attempts to physically harm her. Kyeong-ho jumps in to rescue Sun-hui and unfortunately loses his own life in the process.
Nowadays, Soo-yeon opts to walk home rather than heading to the police station. Nevertheless, Jin-hyeok, the father of Sun hui, notices her walking on the street and gives her a ride home in his car. At home, Sun-hui attempts to discuss the fire with her mother, but Eun-joo remains indifferent. She is unwilling to discuss the event and pretends that everything is fine.
At the police station, the officers discover a link between Soo-yeon and Kyeong-ho. Detective Dong-ho emphasizes that Soo-yeon was present at the crime scene that morning, whereas Sung-woo claims she was absent from school that day. That evening, Soo-yeon regains consciousness in Jin-hyeok’s vehicle before he strikes her on the head, rendering her unconscious.
Nevertheless, Soo-yeon is able to regain consciousness and flee from the vehicle while Jin-hyeok is retrieving something from the trunk. Sun-hui attempts to contact Soo-yeon but is unsuccessful in reaching her. She reflects on the enjoyable moments she shared with Hyun-woo and Kyeong-ho and becomes emotional. Sun-hui attempts to search for news updates on the fire and once more becomes overwhelmed.
The following day, Hyun-woo arrives to take Sun-hui to Kyeong-ho’s funeral. Both of them show their respect to Kyeong-ho and his parents. While leaving, Sun-hui loses consciousness and collapses. Jin-hyeok arrives and takes Sun-hui home from the funeral parlor. The police arrive outside the house to question Sun-hui.
Upon Jin-hyeok exiting the vehicle to converse with them, Sun-hui discovers the swan keychain inside the car and takes hold of it. She remembers the last time she was with Soo-yeon and notes that Soo-yeon hasn’t been responding to her calls. Sun-hui comes to the conclusion that her father is implicated in the incident as well, which frightens her. Sun-hui and her parents are seated in the house, facing the detectives while Sun-hui responds to their inquiries.
The detectives depart without discovering any cause for concern. Jin-hyeok compliments Sun-hui on her strength. Jin-hyeok vows to safeguard Sun-hui under any circumstances. Detective Dong-ho, outside of the residence, determines that Sun-hui seems to be at fault. Sun-hui attempts to contact Soo-yeon in her room and becomes frightened when she is unable to make contact. She requests the address of Soo-yeon’s residence from Hyun-woo and then goes to visit.
Sun-hui meets Soo-yeon’s roommate and adoptive sister there, who discloses that Soo-yeon had not come back home after going to school the previous day. She explains that Soo-yeon would frequently vanish when facing difficulties. The head of the section at the police station instructs Dong-ho to conclude the case as it was deemed an accident.
At that moment, the forensic specialist arrives and announces that Kyeong-ho’s cause of death was a stab wound. Dong-ho and Sung-woo inform their boss that they now have even more motivation to look into the case. That evening, Sun-hui returns home and attempts to follow Soo-yeon’s route. She encounters Choi Hyun-min in the alley by her home, who identifies himself as a kin of her father, Jin-hyeok.
Hyun-min inquires of Sun-hui if she is aware of the occupant of the street-view room in her home. Sun-hui seems bewildered while Hyun-min expresses regret for the strange exchange. He departs, pledging to reunite with Sun-hui. Prior to departing, Hyun-min quietly tells Sun-hui to watch out for her parents. Jin-hyeok observes the interaction from his room.
In a flashback, Kyeong-ho requests his father to critique his artwork but as a renowned painter, he describes Kyeong-ho’s painting as ordinary, leaving him hurt. While at school, Kyeong-ho and Sun-hui opt to draw portraits of one another. Sun-hui compliments Kyeong-ho’s painting, uplifting his spirits as he begins to develop feelings for her. The episode concludes with Kyeong-ho clutching the painting that Sun-hui created for him.
Sun hui’s family is really weird. I can’t wait to know what it is they are hiding.