Hwang Tae Hee is the daughter of a chaebol and team leader at her workplace. When Bong Joon Soo and Baek Yeo Jin both begin to work in her team, they become her love interest and troublesome rival respectively. Tae Hee has to juggle her challenges in love with those in work, helping shape her boss and department director, Goo Yong Shik, from an insensitive and uninterested second generation chaebol to a true leader. Tae Hee's seeming success in love, however, presents her with another problem as she begins to realize that marriage involves just as many obstacles to overcome.

Kim Hyun Joon is an assassin who belongs to a top secret organization known as the "NSS" whereas T.O.P is an assassin who works in another secret organization located in the United States called "IRIS" and was ordered to kill Hyun Joon. Seung Hee is a psychological analyst who plays an important role in bring Hyun Joon into the "NSS." Jin Sa Woo is Hyun Joon's enemy and falls in love with Seung Hee as well.

A would-be singer has been preparing for her career for 3 years. The day before her debut she hears some shocking news which throws her into despair.

An unemployed loafer who meets her by chance and the two fall in love.

A representative of an entertainment company meddles in these two lovers' relationship.

Hong Sun Hee is a strong, happy go lucky housewife who accidentally meets her first love, Jang Dong Chul, again. But now he is known as Song Jae Bin to the whole entire world. Dong Chul became a famous star and didn't recognize Sun Hee the first time that they met because she looked like an old ahjooma. But back in high school, she was the prettiest girl. Sun Hee is already married to a man who always lands their family in debts.