김비서가 왜 그럴까

After his personal assistant tells him that he’ll need to find a replacement, vice-chairman Lee Yeong-jun has trouble falling asleep.

Mi-so’s reaction to his proposal confounds Yeong-jun, but while others may think he’s brilliant and handsome, she just sees an impossible narcissist.

Yeong-jun takes Yu-sik’s advice to heart and tries to impress Mi-so with romance but is taken aback when he hears that she’s gone on a blind date.

Young Joon gets infuriated with jealousy after Mi So went to the blind date. They visit Yumung Group’s art center to expedite the opening, but accidentally get trapped in the library section and spend a romantic moment together. Meanwhile, Young Joon’s brother Sung Yeon returns to Korea after 3 years abroad to visit his family. However, something is not quite right the way Young Joon greets his long waited brother home.

Love and an ordinary way of life are not in Vice Chairman Lee’s repertoire, but he makes a valiant effort to profess his feelings to Mi So, his personal secretary, who feels otherwise. However, he continues on with his heart to fight off his elder brother, Sung Yeon, who suddenly appears in Mi So’s life, and finds a way to apologize to Mi So for his actions. Meanwhile, a wager on Mr. Ko suit rustles up the workplace.

Mi So requests a leave for the first time in her nine years of service. But she does not know what to do and where to go because she has never taken a day off before. Meanwhile, Young Joon, who can’t deal with Mi So’s absence, misses his secretary so dearly that he compromises to resolve his loneliness by joining Mi So on her day off. With great surprise, she gets a phone call from her blind date, Byung Heon, and finally hears about the boy whom she has been looking for.

Secretary Kim grows closer to Sung Yeon knowing he was the one she was with when she was kidnapped. They visit a similar area they were kidnapped hoping it will help them remember fragments of their lost memory. The sight of Secretary Kim and Sung Yeon together drives Vice Chairman Lee mad to the point he professes his love to Secretary Kim once again. The tension between the two brothers heats up, while Gui Nam does everything he can to keep his ordeal a secret by following Ji Ah to the company retreat.

Young Joon invites her to his house for dinner. Although she has visited his house almost every day for the last eight years, Mi So feels totally different this time and gets very nervous. Young Joon awaits her with a surprise gift to make her heart melt. Later on, Young Joon and Mi So get to celebrate the opening ceremony of Yumyung Art Center. Now everyone’s eyes are on the Book Concert, and there Sung Yeon makes a disturbing speech. Mi So can’t help herself but worries about Young Joon only. What’s wrong with her?

Finally, the long-awaited official relationship between Mi So and Young Joon begins! Her faithful response to his genuine love sends him to the highest mountain peak—figuratively speaking—where he shamelessly screams, “Kim Mi So is my woman!” However, their desire gets the whole office's attention, and puts Mi So in a position to set things right that leads to their first official fight.

Everything is pointing to Young Joon—that the boy Mi So is looking for is not Sung Yeon, but him. Mi So doesn’t really understand why the whole family of her boss is lying about his real identity. To confirm her speculation, she pays a visit to Young Joon’s mother and finds a clue that might lead to her childhood hero. Meanwhile, Young Joon figures out that somehow Mi So’s sisters are not going to accept him easily. To win their hearts, he joins Mi So’s family on their vacation trip.

Haunted by the past, Mi-so decides to confront Yeong-jun about what he knows, but she’s not the only one wrestling with timeworn memories.

Yeong-jun shows up at Mi-so’s place with a suitcase. Mi-so’s cooking isn’t up to his usual standard and they both fret about seeing a bad luck sign.

Just when he makes his move, Yeong-jun gets an emergency call and Mi-so is left wondering what she should do. Yeong-jun and Yu-sik go to France.

Yeong-jun introduces Mi-so to an old family friend who went to the same MBA school in the U.S. with him, but she’s surprised to find it’s a woman.

Mi-so is mortified when her father catches her with Yeong-jun in a compromising position and gets worried when Yeong-jun doesn’t answer his cell.

Yeong-jun suggests that they go out to eat together just when Mi-so gets a call from his mother wanting to have dinner -- but only with Mi-so.