Episode 6 of "Phantom Lawyer" begins with I-rang's interrogation by Prosecutor Kim, who is frustrated by his responses. Meanwhile, Na-hyun updates Kim Tae-jun, attributing I-rang's outburst to mental health issues. She notices his wife asleep in the next room, so Tae-jun confesses about bringing in Sang-ho for help when he failed to find a cure. Elsewhere, Do-gyeong's assistant informs him that the CCTV leading to where I-rang found the body was destroyed, thus not capturing him. He asks him to follow I-rang, as he was puzzled about how he found the body and all the other strange events his clients described about him.
After I-rang is released, Kyung-hwa takes him back to his office. She is worried that continuously dealing with the ghosts will put her son in danger, so she wants to burn all the talismans at the office. Surprisingly, I-rang has come to terms with being a ghost lawyer and finds it more fulfilling. He feels lucky to be able to communicate and help souls. He assures Kyung-hwa that he will not put himself in harm's way, and if anything like that happens, he will stop being a ghost lawyer.
With his mother on board, I-rang continues investigating Sang-ho's case. This time, he visits Su-jeong at the detention center. The deal with Sang-ho was for him to stay far away to avoid a possession, but the ghost cannot help but follow him. At the same time, Do-gyeong's assistant bribes a guard to get close to I-rang during the meeting to record their conversation. Sang-ho happens to see the guard and realizes his intention, so he follows I-rang to tell him about the recording.
Inside, Su-jeong gets emotional, and Sang-ho possesses I-rang. After an emotional conversation between husband and wife, they learn that Su-jeong did not turn herself in because Kim Tae-jun was the killer.
She knew that when the issue of Sang-ho's research being halted came up, her father would be targeted as a suspect. To protect her mother, she confessed, thus taking the fall while investigators searched for the real killer. Meanwhile, Na-hyun persisted in her mission to help Su-jeong by finding the real murderer. She had a suspect in mind and needed I-rang's help to investigate the clues. She headed to his office, pretending to believe that he could see and talk to ghosts.
The suspect she had in mind was Gu Hyo-jung. After her visit to the lab earlier, she felt that he was too eager to offer information, as if trying to shield himself. Through their conversation, he subtly established an alibi and led her to suspect Kim Tae-jun. Na-hyun insisted that it was disturbing how Su-jeong could sleep soundly until dawn after having a huge fight with her husband. Sang-ho informed them that Su-jeong suffered from insomnia and that Hyo-jung had given her a calming chamomile tea to help her sleep.
It turned out that Hyo-jung had a crush on Su-jeong before she got together with Sang-ho. After their marriage, he stopped pursuing her, so Sang-ho thought it was over. Obsessive love could be a motive for murder, but it was still not enough. Na-hyun found an even more convincing motive. Hyo-jung was a senior researcher, and with Sang-ho's death, he was next in line to become chief after Kim Tae-jun's resignation. News reports proved that Tae-jun had scrapped Hyo-jung's research into animal cloning, which showed that he harbored resentment towards him. With Tae-jun's resignation, Hyo-jung's first priority was to resume his research.
With all the evidence pointing to Hyo-jung, the only bottleneck was his iron-clad alibi. The CCTV cameras showed him entering the lab but not coming out, which supported his claim that he was working when the murder happened. However, Sang-ho informed them that there was another exit from the lab without CCTV, used to move animals in and out of the lab behind the watchful eyes of animal rights activists. The murder weapon described in the autopsy report was similar to a hook used in the lab to handle the animals.
While Na-hyun headed to the prosecutor's office to request a test on the chamomile tea, Bong-soo and I-rang went to the lab to look for the murder weapon. Unfortunately, there were too many of them, and certainly Hyo-jung must have a sure way to get rid of the blood.
To ascertain the identity of the murderer, I-rang devises a unique plan, enlisting the help of Na-hyun and Bong-soo to stage an elaborate performance designed to elicit a confession from Hyo-jung. However, the plan takes a surprising turn when Sang-ho unexpectedly takes control of I-rang, transforming the act into a confrontation between the two. Hyo-jung, feeling a deep hatred for Sang-ho, confesses that he had previously relied on Su-jeong and Kim Tae-jun but was replaced by the newcomer.
The scene becomes chaotic as Bong-soo's mistake sparks a fire, prompting the sprinklers to activate, forcefully ejecting Sang-ho from I-rang's body. Hyo-jung, initially fooled by the performance, nearly attacks I-rang before Na-hyun intervenes by releasing the animals. The police subsequently arrest and charge Hyo-jung with Sang-ho's murder.
Meanwhile, Su-jeong's mother's life hangs in the balance. In one final act, Sang-ho possesses I-rang and uses his body to develop a cure for her, giving her family a miraculous chance to continue living in his absence. With his emotional attachment resolved, Sang-ho prepares to pass on, and the priest burns his talisman.
I-rang expresses gratitude for the support and care of those around him, particularly pleased that Na-hyun chose to believe him. Meanwhile, Na-hyun remains puzzled by I-rang's mysterious deal but is happy to have won a case with his help. Elsewhere, Do-gyeong receives the recording sent to the guard but discovers it's a mocking message from I-rang.
As the episode concludes, a new talisman is revealed, distinguished by its unique drawings and white color. A cold gust of wind blows into the room, startling I-rang as he looks up in shock. The scene ends with a sense of anticipation for what's to come.
