In the opening of Episode 9 of Pro Bono, Dr. Oh reluctantly allows the team to stay, solely because of their new rich client, Eliyah. Da-wit attempts to flatter both him and Jung-in, but Dr. Oh dismisses him as a "monster" with a "brat" of a daughter. She offers Dr. Oh her favorite mint candy, insisting that she only cares for him. Meanwhile, Gi-ppeum confronts Jae-beom, who confesses that he framed Da-wit with the bribery trap. It's just the first step in his plan to make Da-wit pay. Gi-ppeum agrees to review his evidence but momentarily forgets about client confidentiality, meaning she can't report his confession. He then turns himself in for his ongoing fraud investigation, claiming that he just wants Da-wit to pay.
Gi-ppeum delves into the case - 10 years ago, CEO Yoo Baek-man, Jae-beom's father, was sentenced to a maximum of 7 years in prison for a fire at his Woongcheon Paper Mill. A 17-year-old worker had died due to the mill's outdated electrical system that had short-circuited and lacked proper fire exits. Initially, the factory manager was charged, but Da-wit had him released on bail and changed the defendant to CEO Yoo. Upset, Yoo died in prison.
A judge isn't allowed to interfere in the prosecutor's investigation. Da-wit also leaked an evidence photo - the dead boy's cup noodles - suggesting that the poor boy worked in unsafe conditions. The public was outraged at CEO Yoo, and after the verdict, Da-wit rose to instant fame as the "People's Judge."
Gi-ppeum also notices that all witness testimonies changed to implicate CEO Yoo as a selfish and ruthless boss. The scene is vividly portrayed as the tension between the characters escalates, with each action and reaction contributing to the escalating drama of the episode.
She informs Yeong-sil, Nan-hui, and Jun-u of the developments. The others are conflicted and want to believe that Da-wit had a reason for his actions. Jun-u also notes that their team will be destroyed if they lose their leader. However, there is no cup noodles in the evidence list and it might be fabricated by Da-wit to garner public outrage. Jae-beom also obtained a statement that the factory manager was coerced by Da-wit to testify against CEO Yoo. Meanwhile, Jung-in discovers that Jae-beom has met Gi-ppeum and believes her father is involved. She confronts Dr. Oh and warns him of the risks he's taking with the firm. Dr. Oh simply eats his candy and reminisces about how he bought the candy factory to prevent it from being discontinued. Instead, Dr. Oh pushes her to step down for threatening him about CEO Jang.
Right then, the news reports that Chief Shin, Da-wit's former boss, has reversed his verdict and declared CEO Jang as innocent. Da-wit is being accused of manipulating Jang's trial. Everyone is upset, but especially Yeong-sil, whose surname is Jang and comes from a wealthy family. The partners blame Jung-in for hiring Da-wit and ruining their reputation. She doesn't get a chance to fix things as Attorney Kim forces her to resign.
Gi-ppeum informs Da-wit about Jae-beom's lawsuit and wants to hear his side of the story. He is shocked and rushes off to confront Jae-beom, who is now in prison. He wants to know who the mastermind is and a flashback reveals that Jae-beom actually gave Da-wit a box of apples. After Da-wit passes out, Jae-beom switches the box with money. Jae-beom plays the victim but doesn't receive any sympathy from Da-wit. It turns out that CEO Yoo is responsible for the amputation and death of Da-wit's mother!
Next, Da-wit learns of Shin's verdict through Reporter Kim who calls for a comment. Da-wit confronts Shin about being Jae-beom's accomplice, questioning why a trusted mentor would betray him. Shin acts ignorant, but Da-wit realizes he's scared, as Jae-beom turning himself in was not part of his plan. This means someone else is the mastermind. He calls his spy and has him follow Shin.
Da-wit's hectic day isn't over as Jung-in calls him to the bar where she's drinking. She apologizes for dumping him, but he knows that Dr. Oh forced her. She doesn't blame Da-wit for her resignation and sadly jokes about their promise that they'd marry if they were still single at 40. He looks sad as she reveals it's her 40th birthday.
It seems like someone is out to get Da-wit. Gi-ppeum's mom gets a debt collection notice from their former creditor, JC Capital, even though they should have been exempt after Da-wit ruled in their favor. On top of that, Dr. Oh orders the Pro Bono team to take Jae-beom's case. Later, Nan-hui spots Jun-u meeting Dr. Oh alone.
Gi-ppeum wants to do it the right way and begs Da-wit to come clean. Gi-ppeum and Nan-hui believe he rigged Yoo's trial to get popular. Da-wit is hurt and tells them everything about his mother.
In flashbacks, we see that Mrs. Kang works in CEO Yoo's paper mill, where she works overtime for pennies and he doesn't care that she's overworked. Da-wit is about to enter college when Mrs. Kang gets into an accident and loses her hand. Da-wit demands compensation but CEO Yoo insults him and throws him out. No lawyer is ready to take their case, so Da-wit studies on his own to represent his mom. However, CEO Yoo has powerful friends who prolong the case for 1.5 years before dismissing it, which is why Da-wit fails to go to college.
Mrs. Kang gets sicker and gives her wedding ring, the only thing she owns, to Da-wit. She begs him to cremate her so he isn't burdened with visiting her, and she wants him to get successful so no one can belittle him ever again. Since Da-wit breaks his promise by planting a peach tree with her ashes, he decides to be successful for her sake.
At present, Nan-hui and Yeong-sil beg his forgiveness for judging him harshly, but Jun-u and Gi-ppeum believe this just serves as a motive to rig CEO Yoo's trial. Cornered, Da-wit simply smirks and congratulates them for remembering his teachings. He accepts that he rigged the trial and wishes them luck in court.
