Cha Do-kyung was an "it girl" and center of attention during her school days. Thanks to her looks and affluent family background, she was surrounded by many suitors and admirers. On the other hand, Jang Gong-sim, Do-kyung's friend, who always lagged far behind Do-kyung in every aspect felt inferior to her while growing up. However, Do-kyung's accidental one-night stand with Bong-hee, Gong-shim's then boyfriend, led to an unwanted pregnancy resulting in the two getting married.

Fast forward 17 years, Do-kyung became an ordinary housewife with 3 kids and a good for nothing husband while Gong-shim went on to become a celebrity ballet dancer. Their reversed situation made them at odds with each other and they ended up fighting over Hyun-woo who once had a crush on Do-kyung when young. Torn between the two women, will Hyun-woo stick to his first love who became another man's wife or will he marry Gong-shim, the ugly duckling turned into the beautiful swan? Will Gong-shim's efforts to win Hyun-woo's heart be successful?