In the second episode of Pro Bono, the pro bono team stumbles upon Byeol, whose real name is Chloe, a precious creature who had been abused, neglected, and abandoned a year and a half ago by her pampered owner. A dog rescuer, So-yeon, found her and placed her in the care of a dog cafe owner. But now, the original owner, a daughter of an assemblyman and former prosecutor, wants her back. Her counsel, Woo Myeong-hun, a once-acclaimed but now corrupt prosecutor who was brought down by Da-wit, is her defender.
The scene shifts to the courtroom where Da-wit skillfully maneuvers to have the first judge withdrawn and replaces him with a short-tempered but unbiased judge named Choi. However, things take a turn when Ggi-ppeum, who has never been in court before and only quotes from law movies, and Myeong-hun get a fake witness to claim So-yeon threw Chloe's collar. And So-yeon confesses to it.
It is later revealed that the plaintiff had put a shock collar on Chloe. Da-wit initially remains callous but gets deeply disturbed when he wears the collar himself and experiences its brutal shock. The pro bono team is saddened by the developments, but Da-wit rallies them with his determination. He convinces Judge Choi to have a jury trial, much to the dismay of two of the partners who want to stop the case. However, Jung-in stands firm behind her pro bono approach despite already being on thin ice for it.
As the trial progresses, an abused former maid is recruited by Nan-hui, a passionate human rights advocate, to corroborate the story of Chloe's abuse and the shock collar. But her credibility is questioned when Myeong-hun brings up CCTV footage of her stealing the plaintiff's necklace after she was unfairly fired. The drama unfolds with each twist and turn revealing layers of deceit and justice as the pro bono team fights for Chloe's freedom and the rights of all abused animals.
In a poignant closing statement, Da-wit delivers a heartfelt plea on the training of dogs to love and the responsibility of their owners to care for them. To ensure his victory, he issues a chilling threat to the plaintiff's father, warning that the truth about his family's mistreatment of dogs would cost him the election. Furthermore, Da-wit enlists the aid of the pro bono lawyer, Yeong-sil, to craft a fake shock collar, claiming it as evidence of abuse. With Byeol wearing the faux device and the plaintiff forced to lie about the dog's ownership, Da-wit solidifies his win and keeps Byeol. The Judge Choi, who has rescued three abandoned dogs himself, winks at Da-wit as he realizes the plaintiff's lie. Jung-in smiles and leaves the court, her driver being Jae-beom, the conman who had previously framed Da-wit.
In an epilogue, we see young Da-wit fuming as a neighbor's puppy bites him. His anger dissipates when he learns the puppy is being sold due to the bite. He confesses to harassing the puppy and pleads with the owner not to sell it.
