In Episode 4 of Undercover Miss Hong, the story unfolds with a disciplinary hearing where Keum-bo (now assuming the identity of Jang-mi) stands before President Jung-woo, the executives, and directors of Hanmin. Deok-gyu attempts to shift the blame onto Keum-bo, but Jung-woo calls upon Gyeong-dong to explain what happened to the investor’s funds. Gyeong-dong reveals that 3 billion won is untraceable. Jung-woo then tasks Keum-bo with redeeming herself by locating the missing funds, a feat even the national trade market couldn't achieve, making it impossible for an intern like Keum-bo to accomplish.
Outside the meeting room, Albert, Jin-mok, and Yong-gi anxiously wait to check on Keum-bo's progress. Jung-il tries to mock her, but Albert defends her, sparking an argument. Jung-woo calls Albert in and reveals that if Keum-bo fails to procure the funds, she will be fired.
Later that day, Jung-woo speaks with Bok-hee about Keum-bo (Jang-mi) and learns random details about her that leave him confused. Meanwhile, Keum-bo wonders how she can find the missing funds while also trying to figure out Yeephee's identity.
In a flashback, Chairman Kang is seen orchestrating insider trading through Gyeong-dong. In the present day, Chairman Kang berates Gyeong-dong for disappointing him. Meanwhile, Albert talks to his father and tries to find a way to help Keum-bo. Deok-gyu tells his son that the market violation was ordered by Chairman Kang, making Albert upset when Deok-gyu asks him to go along with whatever Chairman Kang decides.
Later that day, Jae-beom meets Keum-bo and reveals to her that Gyeong-dong was involved in several trade manipulations along with OneMillion. Keum-bo concludes that Gyeong-dong cannot be Yeephee and wonders who the real person Myeong-hwi was working with.
That night, over drinks, Jin-mok tells Albert that he should stay out of Keum-bo's issues. Albert claims that he doesn't mind, leaving Jin-mok shocked.
Later, Jung-woo finds himself at Keum-bo's desk and stumbles upon the sand timer he had given her years ago. His initials are inscribed on the timer, and he realizes that Keum-bo is pretending to be Jang-mi. That night, Keum-bo searches for clues about the person Gyeong-dong and the stock trader were working with. Her mother calls her over to the chicken shop after Jung-woo shows up there. Keum-bo's parents, Soon-jeong and Chun-seob, try to set Jung-woo up with Keum-bo.
As Keum-bo arrives at the restaurant, Jung-woo is just about to leave. Instead of walking away, he turns back inside while Keum-bo is talking to her parents. She pushes him out of the shop and drags him outside. She continues her act, alleging that her sister, Keum-bo, dumped him years ago.
Keum-bo claims that she saved up her sister's trash, including the sand timer, still trying to insinuate that she is Jang-mi. Keum-bo's father tells her mother that Keum-bo was talking to Jung-woo, and the two speculate about their relationship.
Keum-bo returns to the shop and tells her parents that she has nothing to do with Jung-woo. She makes it back to her dorm room that night. However, No-ra spots Keum-bo on the street while she is trying to meet her mother in private. In-ja gives No-ra some of her favorite luxury chocolates, praising her for her hard work. In-ja offers to help No-ra with anything she needs. No-ra asks her mother to help save Keum-bo from being fired.
The scene unfolds with a sense of urgency and tension as each character's actions and reactions contribute to the overall narrative. The use of descriptive language helps to bring the characters and their emotions to life, making the story more engaging and immersive for the reader.
That night, Bok-hee, No-ra, and Mi-sook gathered to discuss the rumors about Keum-bo (Jang-mi) that had been circulating on the chat group. Keum-bo was upset by the false information and attempted to reach out to the CEO of OneMillion through the chat group. The next day, a response was posted on the chat group, and Keum-bo left to investigate it.
No-ra was upset when she realized that someone had eaten several pieces of her luxury chocolate. At the same time, Chairman Kang spoke with Ju-ran and Jung-woo about how Keum-bo would never be able to locate the CEO. Jung-woo mentioned the involvement of a company insider in the trade manipulation, but Chairman Kang refused to consider it.
In-ja arrived at Hanmin to meet Chairman Kang and spoke to Jung-woo about Myeong-hwi. She told Ju-ran that she could never fire Keum-bo because she was No-ra's friend. This piqued Ju-ran's curiosity about Keum-bo, and she tried to talk to Bok-hee about their friendship. She asked Bok-hee to continue keeping an eye on No-ra, while Keum-bo told Jae-beom that she was trying to force the OneMillion CEO out of hiding with her cryptic posts on the chat group.
No-ra told Keum-bo that she heard Gyeong-dong's phone vibrating nonstop all day after the posts went up. Keum-bo used a lockpicker to open Gyeong-dong's desk and found a burner phone inside. The girls hid when Gyeong-dong returned to his desk looking for the phone. No-ra, Bok-hee, and Keum-bo overheard Gyeong-dong talking to the OneMillion CEO about keeping his identity a secret from Keum-bo and asking him to stay hidden.
The following day, Keum-bo visited the CEO's hideout location and decoded his whereabouts by asking around food takeout places. She learned that the CEO, Kim Ki-soo, had already escaped. She found shredded documents in the trash and collected them. No-ra and Mi-sook helped Keum-bo piece together the shredded paper, which turned out to be Ki-soo's flight tickets. No-ra informed Albert that Keum-bo would not be coming to work and revealed that she was at the airport. Albert went to the airport and helped Keum-bo catch Ki-soo.
Keum-bo threatened to have Ki-soo arrested and forced him to sign documents proving that he personally placed the insider trading order. The signature confirmed that the funds were with OneMillion itself, resolving the case.
The Risk Management team commends Keum-bo (Jang-mi) for her bravery, and she hands over a report to Albert for presentation to Jung-woo on her behalf. Albert declines to take credit for Keum-bo's achievements, but Keum-bo calls him her partner, which deeply touches him. Jung-woo assigns Albert and the Risk Management team another project. Yong-gi doesn't mind the extra work, but Albert and Jin-mok appear annoyed. Albert hands the team their paychecks, and instead of going out for a meal with her teammates, Keum-bo leaves to go back home.
That day, Bok-hee praises Keum-bo (Jang-mi) in front of Jung-woo, claiming that Keum-bo was the one behind the Q&A file. At the same time, Jung-woo sees the post Keum-bo made about Gyeong-dong's involvement with the OneMillion CEO and the Hanmin trade broker. Jung-woo brings this up with Chairman Kang, who refuses to take action and privately wonders if appointing Jung-woo as President was a mistake.
In private, Jung-woo confronts Gyeong-dong about his involvement in insider trading and threatens to expose him. Gyeong-dong scolds Ki-soo for signing the documents, but Ki-soo backs out of working with Hanmin on any future trade manipulations.
That evening, Keum-bo and her roommates treat themselves to dinner at a restaurant. No-ra uses the camcorder she borrowed from Albert to film videos of them. Bok-hee insists on paying for the meal, and the four head to a rock café next. There, they talk about their secret spots for crying and bond over shared trauma. Keum-bo shares how she used to hide in the library so her parents would not see her cry.
Dong-gi and her colleagues from the Financial Supervisory Service disguise themselves as young men and enter the café. Keum-bo and her friends ignore them and head to the dance floor. By 11:45 pm., the girls rush back, realizing they will not be allowed to enter their dorm. They manage to sneak inside and find the room in disarray. The girls panic, and Keum-bo realizes that someone has gone through her files. At the same time, Hanmin's henchmen attack Ki-soo and kidnap him. The episode ends with Keum-bo discovering someone hiding inside her closet.
