The story of the love lives, marriage, careers and families of single and independent careerwomen in their 30s.

Lee Jang Suk spent some time in a juvenile detention center for stealing wallets from unsuspecting strangers. After he gets out, he meets a sports agent, Nam Jae Il, who helps him achieve his dreams of becoming a top boxer.

Se Ra is an ambitious woman who discarded her long time boyfriend, Hyun Min, in order to join high society. Though she seems weak, she actually has a great determination to fulfill her dreams. Se Ra betrays Hyun Min in order for her to become successful. This in turn causes Hyun Min to hate Tae Sung. The drama also portrays the #1 export industry.

Jin Joo is a half Korean and Vietnamese girl who marries a Korean man, Kang Jun Woo, in order to come to Korea to look for her biological father who abandoned her. The drama is not only about her searching for her dad but also about the cultural differences between her and her husband's family. There is bad blood between the two families, Kim and Kang. The rivalry is even more fueled since Ji Young is still in love with her ex-boyfriend, Jun Woo, even though she is married to Young Min. Kang Sae Mi is Jun Woo's sister and Kim Young Soo is Young Min's younger brother. They want to get married but both families oppose their marriage which leads to the two young lovers living together and expecting a baby out of wedlock. Kang Won Mi is the thoughtless, old maid elder sister of Jun Woo.

Na Bori (Gong Hyo Jin) is a 25 year old woman who desperately wants to be a teacher at the high school she was kicked out of due misunderstanding with her teachers over injuring a group of male classmates. After getting her GED, she rejects job offers from other high schools and works on becoming a teacher at her old high school so she could work side by side with her high school love interest, the art teacher Ji Hyun Woo (Kim Da Hyun). However, the only thing that enables her to get the coveted job is by signing a contract to essentially babysit Park Tae In (Gong Yoo), a troublemaker who attends the same high school. Tae In, a lonely youth, quickly becomes the "jjang", or "king" of the high school, and enjoys playing mean tricks on Bori whose easygoing personality attracts the majority of her students. Noh Jemma (Choi Yeo Jin) is jealous of the relationship between Bori and Tae In, and goes out of her way to get Bori kicked out but she's not the only one against them...