Young Joon has never been turned down by anyone for his entire life. However, Kim Mi So, his secretary, suddenly tells him that she will quit her job. He is suddenly confused by why she would quit and asks for advice from his friend. After hearing his advice, Young Joon tries everything he can to make Mi So stay.

Mi So reveals Young Joon’s secret to Ji Ran to make her give him up. Young Joon does not really understand why Mi So wants to quit her job, so he proposes to Mi So to keep her on his side forever. However, by his great surprise, Mi So rejects Young Joon’s proposal and leaves him dumbfounded and even more confused. Yoo Shik gives him a friendly advice about how to win a woman’s heart.

Young Joon calls Mi So out to the amusement park and gives her retirement present. Mi So gets touched by Young Joon’s new attitude. Mi So, who only cared about her job, goes out on a blind date. Young Joon hears about Mi So trying to get into a relationship and feels anxious about Mi So being with other guys.

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 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 fighting 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 never had a leave 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?

Enough of the chit-chat and let the loving begin. Finally, the long-awaited official relationship between Mi So and Young Joon starts! 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, making it official does have its drawbacks. Their roles clash with each other’s desire that gets the whole office to notice, 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.

Mi So suddenly faints as the memories of being kidnapped rushes back to her. As she lays unconscious on the hospital bed, the boy from 24 years ago who was by her side on that day, tells her exactly what happened that day. He had known all along who Mi So was, and now, he begs her to wakeup. Meanwhile, Lee Sung Yeon realizes why his brother, Lee Young Joon, never pitied his suffering because he knew all along it was him who was kidnapped and not Lee Sung Yeon. Mi So wakes up and bursts into tears finally knowing the person she had searched all this time is standing in front of her. But why didn’t he tell her in the first place?

Young Joon can’t help himself but worries about Mi So because now she remembers what really happened when she was kidnapped. What if she starts to have nightmares from now on just like he has? Young Joon wants to take care of his lover even when she falls asleep, so he persuades her to let him move into her studio for a while. Meanwhile, Sung Yeon finds out that it was not him but his brother who was kidnapped and the reason why Young Joon had pretended to lose his memories.

Clumsy as it may be, there’s nothing stopping Young Joon’s and Mi So’s love. But sadly, when all the time they have is not enough, Young Joon needs to go away on a business trip. They say when your eyes are away from your lover, so is the heart, but upon Young Joon’s return, their affection swells as much as they were apart. But wait, their secret relationship isn’t so secret anymore! Mi So tries her best to cover up her tracks, but it’s no use and who cares! Full steam ahead!

Young Joon and Mi So are now facing obstacles to overcome which they have never imagined before—Young Joon’s “girl” friend and Mi So’s father. Rumors of Mi So spread across the company that she gets ahead by her charming looks to seduce her boss, and people speak ill of her. Young Joon only worries about Mi So getting hurt by the rumors. Meanwhile, Mi So’s last day at work is coming up. Mi So is done with the handover and gets herself ready to leave Yumyung group once and for all.

In the midst of Young Joon’s nonchalant proposal, out pops up Mi So’s dad. He objects the marriage at first but soon realizes Young Joon’s sincere and genuine love for Mi So after sharing a few bottles of soju with him. He approves Young Joon as his soon-to-be son-in-law under one condition—a proper marriage proposal. Young Joon is faced with the greatest challenge of his life. Meanwhile, Sung Yeon consents Young Joon’s destiny with Mi So and even gives him tips on how he should propose to Mi So.

After the proposal, Young Joon and Mi So’s wedding preparations are on track. Young Joon wants to become a perfect husband as he promised, so he plans a perfect wedding for Mi So and himself. However, for Mi So, there is still a lot of work to be done before the wedding, so she can’t spare enough time to prepare with her groom. Young Joon is disappointed by Mi So for her lack of interest in wedding planning, but alas, Mi So prepares something special to cheer him up!