In the 12th episode of "Phantom Lawyer," I-rang's world is turned upside down as he's possessed by an eight-year-old boy, full of energy and mischief. This encounter takes place just moments before he's about to confess his feelings to Na-hyun, leaving him worried about her reaction. The boy, misinterpreting I-rang's question, tells him that Na-hyun was angry and glared at him when he possessed him. This revelation leaves I-rang devastated, fearing that his confession has caused Na-hyun to feel anger towards him.
The next morning, I-rang wakes up sad and disheartened, unable to even bring himself to eat breakfast. Bong-soo shares the news with Kyung-hwa that the ghost is a boy, prompting her to prepare a lavish meal and take it to the office for them. Meanwhile, Na-hyun is still preoccupied with what I-rang wanted to say at the park, so she pays extra attention to her appearance before heading to work.
At the office, the boy's excitement is palpable when he sees Da-bong and possesses I-rang. Kyung-hwa intervenes and stops Bong-soo from sprinkling water on him, opting instead to feed the boy first. Afterward, the boy and Da-bong head out to play, running into Na-hyun in the hallway. They tease her playfully and head to the playground, where Na-hyun watches from a bench while Bong-soo tries to catch up to a possessed I-rang. Da-bong observes that Na-hyun looks at I-rang the same way she sees her mother look at her father - with warm and kind eyes.
Meanwhile, some children spray water on I-rang, causing him to suddenly come back to his senses. Na-hyun tries to help him, and they fall to the ground together. She becomes flustered and runs away, leaving I-rang confused about why she seems angry at him. Da-bong and Bong-soo explain the teasing to him, making him feel extremely embarrassed.
Back at the office, I-rang apologizes to Na-hyun, who worries that being possessed by ghosts might harm him. However, I-rang is not worried because the ghosts he has met so far have all been kind. He continues his search for the boy's identity using the golf ball he found in his pocket. The episode ends with I-rang determined to uncover the truth about the boy and his connection to him.
Na-hyun enquires about the words he intended to share at the park, but recalls her stern gaze and anger. According to the boy, he chose to lie, claiming he had nothing to say, causing Na-hyun's disappointment. Later, she receives a call from her father regarding Do-gyeong. It emerges that he had invited him for acupuncture therapy, and Do-gyeung had agreed. Na-hyun insists that nothing is going on between them and urges him to cancel the appointment. She calls Do-gyeung back, who seems unhappy that Na-hyun has prevented his father from spending time with him.
Meanwhile, Chairman Yang arrives at I-rang's restaurant, only to find it closed for the day. Kyung-hwa discovers him stranded outside and invites him to her house for dinner. When she steps out to attend to something downstairs at the restaurant, Chairman Yang begins to explore the surroundings. However, Kyung-hwa returns before he can snoop into the main bedroom. She escorts him out, and the change in his facial expression hints that he might be faking his interest in her for ulterior motives.
Back at the house, Kyung-hwa ponders why he tried to sneak a peek into the bedroom and recalls that he had asked about case files and notebooks. The next day, Na-hyun takes her time arriving at the office and ignores I-rang's calls. The boy clarifies the misunderstanding, explaining that at the park, Na-hyun looked at him excitedly, as if eagerly awaiting his words. This news brings a smile to I-rang's face and dispels his anxiety about the impending confession.
As Na-hyun's tardiness delayed their search, I-rang decided to take matters into his own hands and embark on a quest to uncover the truth. His first port of call was the local police station, where he inquired about a missing boy wearing yellow rain boots. At that moment, no reports had surfaced, but a woman's hysterical voice from another room interrupted their conversation, revealing that her son was also missing.
While I-rang was taking the boy, Yoon Si-ho, out for pizza, a man burst into the office to file for divorce. To I-rang's surprise, the man turned out to be Si-ho's father, who recounted the tragic events leading to his son's disappearance. He blamed himself for not feeling well that morning but still taking him to school to avoid missing work. Later in the day, his wife was supposed to pick up Si-ho, but she was delayed and sent him a message. Preoccupied with work, he didn't respond in time, and by the time he rushed to the school, Si-ho was nowhere to be found.
I-rang learned Si-ho's name and date of birth from Na-hyun's text and shared this information with Lieutenant Cho Chi-yeong, who happened to be at the counter buying pizza for his son. I-rang revealed his intention to search for the boy at the GSG golf driving range, which had been closed since 2020.
Intrigued by the case, Chi-yeong contacted the police station and learned that a report had been filed about a missing boy with yellow rain boots. He followed I-rang to the golf course and shared the information about the case. As they searched the premises, I-rang left Si-ho in the truck watching his favorite TV show when he saw Na-hyun's text with his name and date of birth. His memories suddenly flooded back, and he hurried to warn I-rang about Chi-yeong's true intentions.
To I-rang's horror, he discovered that Chi-yeong was the one who had kidnapped Si-ho, and there was another boy tied up in one of the dark rooms. A fight ensued between the two men, and I-rang was knocked unconscious.
At the same time, another police officer arrived on the scene, only to be framed by Chi-yeong as the suspect. The officer noticed boxes of pizza scattered near the dumpster and recognized the same brand in Chi-yeong's car outside. He tried to taser him but was quickly knocked out with a gold club by Chi-yeong.
In this tense and dramatic sequence, each character's actions propel the story forward, revealing layers of deceit and danger as I-rang and Si-ho's search for answers leads them into a web of lies and deception orchestrated by Chi-yeong.
Meanwhile, Si-ho, who possesses I-rang's key and is hiding from Chi-yeong, observes him entering one of the rooms and follows with the policeman's taser in hand. Inside, he discovers another boy, tied up and referred to by Chi-yeong as his son. Si-ho administers a taser shock to the boy and then retrieves I-rang to rush him to the hospital.
As I-rang drives out, Chi-yeong regains consciousness and fires at him. In the process, I-rang is shot, but he manages to drive all the way to the hospital before collapsing.
Na-hyun is at the office, worried about I-rang who isn't picking up her calls. She receives a call from the hospital where the staff have contacted her using the number engraved on the pendant she had gifted to I-rang. Na-hyun is left shell-shocked after receiving this call. She runs into Do-gyeong outside who wants to tell her something, but she is in a daze as she drives to the hospital.
At the end of the episode, Na-hyun arrives at the hospital where the doctor declares that I-rang has passed away. His ghost watches as Na-hyun breaks down in tears beside his unconscious body.
