Episode 3 of *Ms Incognito* opens with a poignant flashback to the day Young-ran first stepped foot in Muchang. As the scene unfolds, Dong-min intervenes to halt a vociferous businessman, Kang Sung-tae, from staging a protest outside the local school. Meanwhile, Lee Mi-sun, Dong-min’s sister and the esteemed principal of Muchang Oseon Kindergarten, entrusts him with the task of fetching the new teacher from the bus stop.
Upon arriving, Dong-min is taken aback by the credentials of the incoming teacher, Bu Se-mi, who is, in fact, Young-ran in disguise. He can't help but wonder what would drive her to abandon a promising city career for a humble posting in a remote town. At the bus station, Young-ran’s heart skips a beat as she locks eyes with Dong-min, fearing that he might recognize her. Dong-min, on the other hand, is left scratching his head, pondering if Young-ran is some sort of influencer, yet unable to quite place her.
The drive back to the school is fraught with tension as Dong-min attempts to engage Young-ran in light conversation, only to be met with her frosty silence. Meanwhile, back in the city, Seon-young and Seon-woo are in a huddle with their lawyers, discussing Young-ran’s past and hatching a plan to tarnish her reputation. They delve into her criminal history and decide that a smear campaign would be the most effective way to oust her from their inheritance.
The lawyers propose initiating a character assassination, while Seon-young, ever the strategist, suggests weaving in Young-ran’s mother’s fraudulent past to paint her as a 28-year-old gold digger, hell-bent on marrying into wealth. Seon-young revels in the plan, convinced that public humiliation would be the ultimate key to driving Young-ran away.
Back in Muchang, Dong-min assists Young-ran (now going by Se-mi) in settling into his other house, anticipating her new role at the kindergarten. His curiosity gets the better of him as he probes Se-mi about her educational and professional background, only to be met with a stern rebuff. She demands that he respect her privacy and back off.
Dong-man shares his curiosity about Se-mi with his colleague, Seo Tae-min, as the two ponder over her mysterious identity. Inside the house, Young-ran’s hands tremble as she unzips her suitcase and uncovers a gun, complete with a few bullets. Her mind races back to a harrowing conversation with Seong-ho, where he had implored her to wield the gun against Ye-rim’s killer without a shred of hesitation.
Present-day Young-ran finds herself famished, yet there's not a morsel of food to be found in Dong-min's home. Maintaining her dignity, she stubbornly declines the invitation to join Dong-min and Tae-min as they savor pancakes outside. Meanwhile, Lee Don instructs a factory worker to keep a watchful eye on Young-ran's mother, So-young, who is diligently toiling away at Seong-ho's noodle factory.
Seon-woo crosses paths with a local hoodlum named Dong-hong and enlists his services to locate and eliminate her. Dong-hong consents to track her down but balks at the idea of killing her unless Seon-woo sweetens the deal with more money. That very night, Dong-min convenes with the other kindergartners' parents at the convenience store to deliberate over Se-mi.
He harbors concerns that Sung-tae might attempt to bribe her, as he has done with some of the other teachers, prompting her to make a hasty exit. Se-mi unexpectedly arrives at the store, searching for sustenance, and is taken aback by the sight of the Muchang villagers. She procures a few packets of ramen for her dinner and firmly turns down Dong-min's offer.
The villagers coerce Dong-min into returning home and extend a meal invitation to Se-mi, recognizing her as the new kindergarten teacher. During the journey back, Dong-min and Se-mi engage in another heated exchange, which only serves to irk her further. Se-mi (Young-ran) reminisces about her conversation with Don, where he divulges that Dong-min is infamous for his fiery temper.
Upon arriving home, Se-mi stumbles upon Dong-min's son, Ju-won, who is secreted away inside a tiny tent in Se-mi's new abode. Setting her pride aside, Se-mi requests to borrow some kimchi from Dong-min. That evening, Se-mi (Young-ran) savors her meal and reflects on her encounter with Ju-won. Subsequently, she scours the internet for instructions on how to install several CCTV cameras in the village.
At that very moment, Lee Don forcefully expels Butler Choi and Cheol-su from the mansion, dismissing them on the spot for their attempted harm against the new mistress, Kim Young-ran, following Seong-ho’s tragic demise. The duo resolves to rendezvous with Seon-young while Hye-ji remains isolated in the house. Lee Don takes up residence in the mansion and instructs Hye-ji to notify him should Seon-young attempt any contact.
On her inaugural day in Muchang, Se-mi (posing as Young-ran) embarks on a morning run. Tae-min, seizing the opportunity, poses a series of inquiries to Dong-min about Se-mi, hinting at a budding romantic interest. Meanwhile, Dong-min readies Ju-won for school and requests Mi-seon to meticulously verify Se-mi’s credentials before extending an employment offer.
Mi-seon assures Dong-min of her diligence, mentioning that their cousin, Lee Don, places great trust in Se-mi. By chance, Secretary Ham informs Seon-young that locating Young-ran will be time-consuming due to the inaccessibility of local CCTV footage. Seon-young surmises that Seong-ho had entrusted Lee Don with Young-ran’s safety prior to his suicide and instructs Secretary Ham to involve Lee Don.
Seon-young resolves to file a missing person’s report for their mother-in-law. At Ilseon Kindergarten, Mi-seon conducts an interview with Se-mi and is captivated by her flawlessly rehearsed responses. Impressed, Mi-seon offers Se-mi immediate employment and proceeds to give her a tour of the school premises.
Just then, Sung-tae makes an unwelcome appearance, causing a commotion as he demands Mi-seon to relinquish the property on which the kindergarten stands. He reveals his intentions to construct a nursing home on the site, but Mi-seon firmly rebuffs him. During this altercation, Se-mi overhears Mi-seon’s conversation with a representative from Iseon Women’s University.
The representative discloses that the only Bu Se-mi on record is a 53-year-old woman. Se-mi (Young-ran) promptly contacts Lee Don, urging him to prevent Mi-seon from jeopardizing their scheme. Mi-seon, determined to uncover the truth, decides to contact one of Se-mi’s former employers and is stunned to learn that Se-mi is an imposter.
Se-mi arrives on the scene, brandishing threats against Mi-seon. She calls Don, who attempts to pacify his cousin. Don then reveals Se-mi’s true identity as Young-ran, the late Ga Seong-ho’s wife from Gaseon Group. Young-ran proposes a deal to Mi-seon, offering to compensate her for the land where the kindergarten is situated and requesting permission to remain in Muchang as Se-mi for the next three months.
Mi-seon, swayed by the offer, agrees and addresses Se-mi (Young-ran) as “madam.” The episode concludes with Dong-min’s arrival, where he confronts his sister for according Se-mi such a title.
