When Im Yoona tries to save her relationship with her no-good boyfriend, she mistakenly sleeps with a total stranger, Ji Changwook. Although they try to forget about the one-night stand, Yoona later discovers that she is pregnant. When the family of Changwook, who is the sole male heir to a successful family business, discovers that Yoona is having his baby, they force the two to marry. Will the pushover Yoona learn to stand up for herself or will fate have other plans for her?

Main Characters

Im Yoon A is an unfashionable office lady in a law firm described as a "sticky note girl" - a person who is helpful, but unnecessary and easy to throw away. Her co-workers frequently take advantage of her eager to please nature by dumping unwanted tasks onto her. She plans and pays for a trip on a romantic love cruise, hoping to lose her ity and thus keeping her boyfriend.

Ji Chang Wook is the wealthy sole heir of a soap and cleaning products company. He plans to propose to his long-time girlfriend Sooyoung during the cruise trip, but is unaware that she stood him up for the 11th time and never boarded the cruise until he sleeps with someone who is not Sooyoung.

Choi Soo Young is a professional ballet dancer in New York City and the long-time girlfriend of Changwook. When she gets the part of Odile instead of Odette, she rejects the offer and leaves to go see Changwook on the cruise ship. A sudden call from her manager leaves her choosing ballet over Changwook and standing him up for the 11th time. But when she returns back to South Korea, she finds drastics changes in Changwook's life.

Aiden Lee/Lee Dong Hae is an internationally famous Korean-American designer whose single goal is finding his long-lost biological sister. He meets Yoona by accident, and is intrigued by her kindness. From them on he becomes her Daddy-Long-Legs, encouraging her when she is down and coming to her rescue when she needs help. Constantly worrying about her, Donghae begins to realize that what he feels towards Yoona is something more than protectiveness.

Supporting Characters

Lee Kwang Soo is the assistant to Ji Changwook.

Mi Ran is the mother of Im Yoona.

Yu Ri is the older sister of Yoona.

Tae Yeon is the second older sister of Yoona and is the wife of Baekhyun. She has one son and is pregnant with another on the way.

Baek Hyun is the husband of Taeyeon. He helped his father drug Changwook which ended in a terrible mistake and leaving his sister-in-law, Yoona, pregnant.

Min Sang is the father of Baekhyun. He and Baekhyun drugged Changwook's drink so that he could be caught with a random women they chose. However, Changwook ends up having a one-night stand with Yoona and not the women that they chose.