Episode 8 of "The Art of Sarah" begins with Sarah burning her leftover stocks from old seasons and shedding tears. In her current guise as Mi-jeong, she declares that she has no remorse in killing Sarah, asserting that the latter deserved it and no one cared about her.
The police believe that Sarah is lying about being Mi-jeong to save Boudoir's reputation. If Sarah Kim is a murder victim, Boudoir's fraud case will be closed due to a lack of prosecutorial authority. As a heads-up, Sarah calls Yeo-jin and informs her that with Sarah's death, Boudoir will go to Nox. However, Mu-gyeong is one step ahead as hospitals keep tissue samples of organ donors. He sends Jae-hyeon to get Sarah's tissue sample tested against the Sarah they have arrested.
Sarah tries to stall by revealing how the murder took place, but Mu-gyeong has already guessed it. The launch party is recreated through his eyes – it's a snowy, cold night. Sarah is overwhelmed as most of the guest list hates her. Yeo-jin tries to corner her, and Sarah blandly tells her that she will get her money back the next day.
Chairman Choi Chae-u arrives with Ji-hwon and has him grab Sarah. First, he tries to get answers out of Sarah alone, but she doesn't regret using him. Instead, she points out that they are alike. That's the wrong answer as an upset Ji-hwon has already betrayed her to an extent. He has told Chairman Choi of their plan to seduce her. As revenge, she forces Sarah into a bad contract with a 30% commission.
Next, Da-hye and Hyo-eun graffiti insults at the venue. Sarah is already losing her cool when she finally sees Mi-jeong. She drags Mi-jeong to the venue's office, where the latter attacks her. Sarah gets the upper hand and smashes Mi-jeong's face in. She then tells Choi that she will move into the store that very same night. Thus, Mi-jeong's body, which is hidden in a suitcase, is transported to Samwol Department Store with the rest of Boudoir's items.
Once inside Samwol, Sarah drags the suitcase to the trash chute. She throws Mi-jeong and the purple bag she had gifted her down the sewer. But Mi-jeong is alive and tries to make her way out. She dies of the cold before she can reach above ground. Mu-gyeong claims that Sarah knew Mi-jeong was alive when she threw her in the sewer.
In a flashback, we see Sarah fleeing after knocking out Mi-jeong. Running into Seong-sin, who genuinely celebrates her success, she has blood on her hands and is visibly shaking. He calls her Eun-jae, but she pretends to be someone else. It's safe to assume that Seong-sin stole her tissue sample from the hospital to prevent it from being used against her after Mu-gyeong questioned him.
Everything Mu-gyeong said seemed real, except for the murder's execution. In a flashback, Sarah tries to hide Mi-jeong in the private office. When Mi-jeong becomes agitated over Sarah's refusal to acknowledge her contribution to Boudoir's success, the two fight until Sarah knocks her out. It was actually Mi-jeong who cut the CCTV wires, planning to kill Sarah and take her place. However, Sarah's clientele know her face, which Mi-jeong points out as a flaw in her plan. If Sarah disappears, no one will look for her. The fight escalates until Sarah, fearing for her dream of owning a luxury brand and knowing it would be ruined if she reported Mi-jeong, smashes Mi-jeong's face in.
Presently, Sarah recants all her statements and confesses to murder as Mi-jeong. Mu-gyeong can either release her as an innocent nobody or lock her up as the culprit Mi-jeong. In either case, Sarah and her fraud are out of the picture. The Chief asks Mu-gyeong to wrap up the case since they can never verify that the woman they have is truly Sarah. Helplessly, Mu-gyeong arrests her as Mi-jeong and sentences her to 10 years in prison. As she changes into her prison uniform, we see the transplant scar, confirming that she is Sarah. Mu-gyeong visits her in prison for the first and only time. She is relieved when he shares that Mi-jeong has been cremated and Boudoir is still a success. Before leaving, he asks who she really is, but she doesn't answer. As she is taken back to her cell, we see her in her Sarah Kim attire, suggesting that she always wanted to make Sarah her true identity.
