The episode begins with Hong Keum-bo meeting her informant to gather evidence against Mr. Cho Du-pal, a business owner under investigation for tax evasion. Keum-bo works in the Capital Market Investigation Division of the Financial Supervisory Service. Along with her manager, Mr. Hwang, and colleague, Nam Dong-gi, Keum-bo (also known as "The Pit Bull") meets Mr. Cho before the night of the hearing. She promises to side with him the following day, but in court, Keum-bo flips on them and testifies against Mr. Cho. She provides incriminating evidence against the businessman, who is subsequently booked for fraud.
Keum-bo's manager, Mr. Hwang, is suspended while she is promoted as the new Task Manager. Being the only female employee in her division, news of Keum-bo's promotion is met with a sour reaction from her male teammates, especially Dong-gi.
Keum-bo's boss, Yun Jae-beom, schedules a meeting for the team. During the meeting, Keum-bo reveals that during her investigation of Mr. Cho, she discovered that Hanmin Investment & Securities, a family-run business, was involved in siphoning funds and tax evasion. She claims that the company was run by President Myeong-hwi after his father, Chairman Kang Pil-beom, was embroiled in an assault case.
Keum-bo speaks with the lead prosecutor and asks him to investigate the company. The prosecutor refuses to lead the investigation unless he has serious evidence against the business. Keum-bo is dejected but determined to expose the company.
At Hanmin Investment & Securities, Chairman Kang meets with his son, President Myeong-hwi, as well as his son-in-law, Director Oh. The trio is joined by Song Ju-ran as they discuss the investigation led by the prosecutors. Myeong-hwi grows curious about the task force members, Jae-beom and Keum-bo.
He asks his father to right the wrongs Hanmin Investment committed in the past by agreeing to the investigation. Pil-beom refuses and asks Ju-ran to keep an eye on his son.
Later that day, Myeong-hwi convened a meeting with his general managers, So Gyeong-dong and Cha Jung-il, as well as Manager Bang Jin-mok, to delve into the specifics of the investigation and the potential risks of the prosecutors uncovering any evidence related to the slush fund. He tasked Jin-mok with relocating any existing slush fund ledger and to investigate the task force members, Jin-beom and Keum-bo.
That night, Keum-bo received an anonymous email from a user named Yehppe, revealing classified information against Hanmin Investment & Securities. The sender requested a face-to-face meeting later that night. At the designated spot, Keum-bo was taken aback to see Myeong-hwi, who revealed that he was working with Yehppe to expose his father's fraudulent activities. He handed over a document to Keum-bo, which she could present to the prosecutor as evidence against Hanmin Investment & Securities. Keum-bo agreed to collaborate with Myeong-hwi but warned him about betraying her.
The next day, Keum-bo handed over the evidence to the prosecutor, who decided to investigate the company. She contacted Myeong-hwi to inform him about the raid, and he asked to meet again that night. His secretary, Bok-hee, overheard the conversation and informed Ju-ran about it.
Bok-hee assumed that Myeong-hwi was dating someone, but Ju-ran seemed suspicious. That night, Chairman Kang convened a special meeting to check on his employees and their preparations for the prosecutors who would be arriving at the company the following morning. His grandson and Director Oh's son, Albert, tried to reach out to Myeong-hwi but received devastating news of Myeong-hwi's death.
Keum-bo learned about Myeong-hwi's death by accident and was devastated. She was shocked to discover that the prosecutors had decided to postpone the investigation against Hanmin due to the tragedy. She wrote an email to Yehppe, requesting their continued assistance.
Dong-gi informs the prosecutors that Keum-bo was working with an informant from Hanmin Investment & Securities, leading to her demotion and punishment. Dong-gi is subsequently elected as the new Task Force Manager. One night, Keum-bo meets her parents at their restaurant, where she has a drink to clear her mind. On her way home, two bikers steal her bag, and a group of men attempt to kidnap her. Keum-bo fights back, and the men flee when they hear police sirens. However, the bikers attack the prosecutor, resulting in a severe head injury.
That night, the Kang family gathers for a low-key funeral service. After the service, Director Oh meets Chairman Kang's ex-wife, Choi In-ja, and daughter, Kang No-ra. Both Director Oh and In-ja accuse each other of mooching off Chairman Kang, but he unexpectedly shows up. He announces that No-ra will have a chance to inherit the family business if she successfully completes a three-month probationary period as an employee at Hanmin. Director Oh and Albert are shocked by this suggestion, as Albert was next in line after Myeong-hwi. Chairman Kang asks No-ra to keep her status as his daughter a secret from all Hanmin employees. No-ra tells her mother she is not interested in running the business, but In-ja reminds her that the company may be handed over to Albert if she doesn't take an interest.
Jae-beom meets Keum-bo at the hospital the next day and suggests that she disguise herself as a secretary working for Hanmin to try to find the slush fund ledger. Keum-bo initially refuses to go undercover, but Jae-beom persists in convincing her. One day, Chairman Kang appears at a press conference to talk about his son's death, refusing to accept rumors about Hanmin Investment & Securities. Keum-bo is angered by his comment and agrees to go undercover to find the truth about what happened with Hanmin nine years ago, as Chairman Kang mentioned in his speech.
Ju-ran tells Chairman Kang that all the documents Myeong-hwi had in his office have been destroyed and that the investigation into his accident has been closed. She claims that only two people know about the slush fund ledger and the cache file: herself and Chairman Kang. Chairman Kang insists that even if Myeong-hwi were his son, his priority is Hanmin.
Later that day, Keum-bo goes to her younger sister, Jang-mi's room, to make notes on how to disguise herself for the mission. She pays Jang-mi to give her a makeover and get a haircut and outfit change to appear younger. Keum-bo tests out her disguise by trying to rent an adult movie but runs into Albert and ends up in an argument over the same film tape. The disguise works, and the store owner asks Keum-bo to show him an ID card. She leaves without the tape.
The next day, Keum-bo appears for the entrance exam to join Hanmin as their new employee alongside No-ra. Later, they sit for an interview with other candidates but are ignored during the interview. Keum-bo asks the panel to ask them a question, which helps No-ra pass the interview. Keum-bo challenges the panel by claiming that a question on the test was wrong, which impresses Ju-ran, Jin-mok, and Jung-il who hire Keum-bo based on her intelligence.
The episode ends with Jin-beom giving Keum-bo a list of all Hanmin employees with their background check reports. Keum-bo moves into the Seoul City Dorm for Single Female Workers where her roommates are Bok-hee, No-ra, and another girl named Kim Mi-sook.
