It turns out Sara wants to investigate Yul Seong, and they have no other choice but for her to pretend to get back with him. Gi Jun then meets Yul Seong to confront him, with Chairman Cha Yul's presence there, adamantly denying any chance of Sara returning to her house. Gi Jun enters the office with Yul Seong and asserts that he must be involved in Sara's mother's death, which Yul Seong denies. Right then, Sara enters the room.

She declares her wish to reunite with Yul Seong to see her son, and Yul Seong immediately sets a condition requiring Sara to arrange a meeting with Young Ah. Meanwhile, Gi Jun's heart is shattered seeing Sara returning to Yul Seong; he stands below her apartment all night but doesn't dare to ring the bell.

The next day, Sara informs Director Jang Mi of her wish to take a two-month leave to get back with Yul Seong. Everyone is panicked by this news. Sara then explains to everyone her plan to deceive Yul Seong.

She arranges for Yul Seong to meet Young Ah. Young Ah bluntly states she detests Yul Seong and is only meeting him for Sara, and today's meeting would merely be a simple meal. Despite the humiliation, Yul Seong still swallows his pride because at least he gets a chance to approach Young Ah.

Just then, his mother walks in, about to scream as usual but stops upon seeing Young Ah and doesn't dare to say anything, only greets her with a smile. After Young Ah leaves, Yul Seong is visibly excited, but Sara says if he wants to continue, he needs to sign a clear marriage contract. Sara gets custody of their child, and if they divorce, Yul Seong must pay her 3 billion won. Yul Seong agrees to 2 billion if Sara helps with his project. Sara agrees. However, the next day, the police enter Solution's office with a search warrant, accusing Sara of providing legal advice illegally as she couldn't practice law having been released from prison a year ago and sharing commissions with Gi Jun. Gi Jun says that he has always been with her as a legal advisor, so the first accusation can be clarified. Right then, Chairman Cha Yul walks in, revealing she was the one who had anonymously accused Sara, to warn her about messing with her son. Sara later meets with Yul Seong and suggests ending their collaboration if he continues to let his mother manipulate everything. She uses gentle words to evoke his empathy. Upon returning to the office, she is informed that the police have confiscated a double-entry accounting book from Solution, proving the company's fraud. However, no one knew about this book, and Sara suspects they have been framed. Upon checking the CCTV, they discover the hard drive was stolen.

Sara realizes the thief is someone inside the team who knew Dae Ki could recover data, so they didn't just delete the CCTV but also stole the hard drive. She enters Hee Jin's room and quickly finds the CCTV hard drive in her drawer, realizing she has been Cha Yul's spy all along. It turns out she wanted to win Hui Won's favor and had conspired with her to trap Solution. Gi Jun feels Sara is struggling too much and tells her not to try to get back with Yul Seong anymore, but Sara refuses, so he resigns and leaves soon after. Not long after, Sara officially returns as the daughter-in-law of the Cha family, surprising her mother-in-law. When she calls yul seong to make a scene, Sara shows her the contract with Yul Seong and walk away. In the meantime, Gi Jun opens his own law firm, and Dae Ki and Kang Bom come to visit him. Eventually, Seo Yeon returns, and Sara is overjoyed to reunite with her son after a long time. That night, Chairman Cha Yul threatens Sara again and forces her to sleep with Yul Seong to prove her sincerity in wanting to reconcile. Yul Seong also speaks up, suggesting that they should let Sara be comfortable. Hui Won suddenly stands up and demands Sara bring fruit to her room. Sara complies but brings the fruit cut in the way it is offered to the dead in Korea, aiming to tease her. Sara also reminds her that a daughter-in-law is a guest in the house and she should behave accordingly.

While Cha's mother and daughter are away, Sara sneaks into her room to check their schedule on the day her mother died. It turns out that both were not at the crime scene. Sara takes a screenshot and tries to erase any traces before planning to leave. However, as she is about to leave, Hui Won opens the door and enters, and Sara hides behind the door. Luckily, Seo Yeon runs back and tells his grandma to go play with him, saving Sara who is shaking behind the door.

Meanwhile, Dae Ki and Kang Bom at Gi Jun's office see the case diagram of Yoo Mi and offer to help him find the whereabouts of the taxi driver. They trace him to a parking lot, where Dae Ki approaches the driver's car to investigate and finds Hui Won inside. It turns out she is the one who eliminated Yoo Mi, not her son.

Hui Won tells the taxi driver to flee because a group of lawyers is investigating his case. She throws him some money and tells him to leave or he will go to jail.

The next day, the taxi driver comes to Cha's house, and Sara approaches him to ask about the shoes he is wearing. He reveals that they were Yul Seong's old ones and had been given to him. After that, she comes to visit Gi Jun, and they realize the driver is also the person who took Sara's mother away from the prosecutor's office, and he also works for Chairman Cha and the mother and child of the Cha family had not scheduled their work correctly. The next day, Sara invites the driver Deuk Goo to the Solution office, showing him CCTV footage of him leading her mother out of the prosecutor's office, but he vehemently denies it. Afterward, Deuk Goo meets Yul Seong and attempts to extort money over Sara discovering him. However, Yul Seong confidently says that the person recorded is him and no one else, so Deuk Goo would still be the one to blame. From there, when Yul Seong returns home, he checks everywhere for hidden cameras, just as Sara comes back and shows him the CCTV footage. She says Gi Jun showed her that footage, and when he denies it, Sara leaves, saddened, which seems to also lower Yul Seong's guard. That night, Yul Seong is informed that the Cha Yul Town project has been approved, praising it as Sara's achievement, but Hui Won says it wasn't her doing. Later, Sara calls Young Ah to thank her, revealing that the bill was going to pass anyway, but they had staged a play to make the Cha family respect Sara. Meanwhile, Hui Won scolds her son for trusting Sara, he is fed up to the neck and criticizes back for Hui Won's trust in Deuk Soo. After finishing his piece, he leaves. That night, Yul Seong comes home drunk, and Sara uses the opportunity to unlock his phone with his fingerprint to read his messages but finds nothing suspicious except for a message arranging a meeting at 8 am the following Monday. She immediately informs Gi Jun, and he finally acknowledges that her return to the house was beneficial. That day, Gi Jun, Kang Bom, and Dae Ki follow the driver's car, stage an accident, and kidnap him. They then bring the car to a meeting point at a car demolition site and use his phone to signal their arrival. The driver's car is quickly crushed by another car, and it turns out Solution is the savior of his life. Yul Seong had lured him there as a trap to eliminate him. At that moment, Sara arrives and asks the driver what he had done with her mother. He says he only followed Yul Seong's orders to lure Sara's mother outside, and then they leave him on the side of the road, at which point Sara's mother had been drugged. Gi Jun was about to ask him more about Yoo Mi when he requested to smoke a cigarette first. At this time, Sara was almost fainting upon learning that Yul Seong had harmed her mother. Everyone was worried and came to help her stand when the driver took the opportunity to flee and jumped into a car intending to escape. However, as soon as he drove out of the parking lot, he was immediately hit by another car and the driver was promptly taken to the emergency room. A flashback shows the day Sara's mother died; before that happened, she was brought by Yul Seong to the rooftop of the construction site where Sara's father had died. He interrogated her about why she was going to the prosecutor's office, only to find out that upon learning about Na Yoo Mi's situation, she had gone to meet Yul Seong to threaten to report the matter to the police if he did not help Sara get out of jail. He chased her away, and so she went to the prosecutor's office. He snapped at her, grabbed her by the throat to ask who had told her about Na Yoo Mi's situation, and when she refused to speak, he pushed and she fell, accidentally falling off the rooftop.

It turns out that right after learning about Yoo Mi, Sara's mother went to meet Yul Seong and threatened to reveal Yoo Mi's existence to the police if he did not help get Sara out of prison, where she was wrongfully held.