What's Wrong with Secretary Kim

Vice-chairman Lee Yeong-jun struggles with insomnia after being informed by his personal assistant that he must find a new replacement.

Mi-so is unimpressed by Yeong-jun's proposal, seeing him as an unattainable narcissist rather than the brilliant and handsome figure others perceive.

Yeong-jun follows Yu-sik's suggestion to win Mi-so's affection through romantic gestures, but his efforts are disrupted when he learns she has attended a blind date.

Young Joon becomes jealous when Mi So goes on a blind date and they end up accidentally locked in the library of Yumung Group's art center, leading to a romantic encounter. At the same time, Young Joon's brother, Sung Yeon, returns to Korea after three years overseas, but Young Joon's reaction to his arrival seems unusual.

Vice Chairman Lee, unaccustomed to love and normalcy, tries to express his feelings for his secretary, Mi So, who does not reciprocate. As he competes with his unexpected rival, Sung Yeon, who enters Mi So's life, Lee seeks to make amends for his past mistakes. At the same time, a bet involving Mr. Ko's business dealings causes tension in the office.

Mi So, who has never taken a day off during her nine years of service, requests leave but feels uncertain about what to do with her free time. Meanwhile, Young Joon struggles with her absence and decides to spend the day with her to cope with his loneliness. At the same time, Mi So receives a call from her blind date, Byung Heon, who may be connected to the boy she has been searching for.

Secretary Kim and Sung Yeon grow closer as they revisit a location tied to their shared, lost memory of being kidnapped, hoping to recover fragments of the past. Vice Chairman Lee, seeing their growing bond, becomes increasingly unhinged and declares his love for Secretary Kim once more. Meanwhile, tensions rise between the brothers, and Gui Nam tries to conceal his secret by secretly following Ji Ah to a company retreat.

Mi So visits Young Joon's house for dinner, feeling unusually nervous despite her frequent visits over the past eight years. Young Joon surprises her with a thoughtful gift, deepening her emotional turmoil. Meanwhile, at the opening of the Yumyung Art Center, Sung Yeon delivers a provocative speech during the Book Concert, causing Mi So to become increasingly concerned about Young Joon.

Mi So and Young Joon's relationship takes an official step forward as their feelings for each other become more public, drawing attention from their coworkers. Young Joon's emotional declaration of love for Mi So causes a stir at the office, leading to tension when Mi So tries to downplay their relationship, resulting in their first serious argument.

Mi So begins to suspect that the boy she has been searching for is not Sung Yeon, but Young Joon, and she becomes determined to uncover the truth behind her boss's family's deception. She visits Young Joon's mother and discovers a potential clue related to her childhood hero. Meanwhile, Young Joon realizes he must gain the approval of Mi So's skeptical sisters and decides to join her family on their vacation to do so.

Mi-so seeks answers from Yeong-jun regarding a shared past, but others in her life are also grappling with their own unresolved histories.

Yeong-jun arrives at Mi-so's home carrying a suitcase, and the two become unsettled when they notice that her cooking is not as usual, interpreting it as an omen of misfortune.

Yeong-jun receives an unexpected emergency call just as he is about to take action, leaving Mi-so uncertain of her next move. He then travels to France with Yu-sik.

Yeong-jun introduces Mi-so to a former family friend and fellow MBA school classmate from the U.S., to her surprise, as she had assumed the friend was male.

Mi-so is embarrassed when her father discovers her in a compromising situation with Yeong-jun, and she becomes concerned when Yeong-jun stops responding to her calls.

Yeong-jun proposes a meal together, but Mi-so receives a call from his mother inviting him to dinner—alone.