As Episode 4 of Pro Bono unfolds, Da-wit stands at a press conference, aiming to rally public support. The reporters shower praise on Gang-hun, who exudes maturity in the face of adversity. However, Gi-ppeum cautions Da-wit against using Gang-hun as a mere PR tool. This time, Da-wit is offended, believing his intentions are being questioned. He declares that they are incompatible and one of them will surely leave the team.
As the day draws to a close, Jung-in asserts that Da-wit is crossing the line by targeting CEOs. She not only threatens to disband the team but also reveals that she has the power to land Da-wit in prison for the fabricated bribe.
In a quiet moment, we see Gi-ppeum learning sword dancing to release her pent-up frustration. Meanwhile, Gang-hun engages in an online Go match with an anonymous opponent. So-min returns home to find her son engaged in this activity, believing he sees her as a poor parent. Gang-hun's research on adoption has caused her hurt, as she fears he's looking for a way out.
During the second appeal hearing, Da-wit persuades Judge Kook for an on-site inspection. Kook and Myeong-hun spend the day in wheelchairs, encountering numerous obstacles and even falling from their chairs at one point. Myeong-hun empathizes with the struggles of a disabled child but maintains that the issue lies with the parents and not the hospital. He even goes so far as to question So-min if she regrets having a child. She breaks down, insisting that she doesn't.
That night, So-min drinks and reflects on her own mother who abandoned her on this day. She hates that she's become like her mother but also yearns for her return. She almost jumps from a bridge until Gang-hun calls the lifeline payphone and stops her. She turns to see the pro bono team who helped him reach the bridge. Gang-hun cries, blaming himself for being a burden. By seeking adoption, he had hoped So-min could move on with her life. She assures him that she loves him and they embrace.
In the subsequent hearing, CEO Choi Woong-san, a man of quiet strength and a passion for the game of Go, strides in with his cane, his calm demeanor a testament to his belief that every life is equally precious and beautiful. Da-wit, however, lashes out in frustration, arguing that inequality is the norm for those without a safety net, his mother's sacrifices for his education hanging heavy in the air.
As the hearing concludes, I-na's tech companion updates Da-wit with the shocking news that Judge Shin, who was supposed to be Da-wit's stepping stone to the chief justice position, has been nominated for the role himself. The timing couldn't be more ironic.
The next hearing takes an unexpected turn when it's revealed that Woong-san's charities are dedicated to empowering the disabled. Gang-hun, who is attending one of these schools for free, steps forward to share his own story of bullying and rejection due to his crush on a classmate. He pleads with Woong-san for guidance on how to live a life without being a burden.
On his way home, Woong-san witnesses a protest from So-min's neighbors against a special needs school being built in their neighborhood. The next day in court, he reveals his own connection to Gang-hun, a once online rival turned friend, and his desire to prove that the child is not a burden. Woong-san decides to adopt So-min and, in doing so, takes Gang-hun under his wing as his grandson.
The audience learns that while Woong-san is not pro-life per se, he supported the cause in memory of his son and truly desires to help others. He announces his plan to use the anti-abortion budget to build a special needs school, a gesture that prompts Da-wit to drop the case.
As they depart, Gi-ppeum secures the video evidence of Da-wit's unknowing bribe. In the epilogue, Yeong-sil discovers that So-min visits the same bridge every year on the anniversary of her mother's abandonment. They decide to remodel the lifeline payphones so they can reach out to her in case of emergency or reckless behavior. It is through this small act of kindness that they ultimately help Gang-hun find So-min.
