"You Who Rolled In Unexpectedly"tells the story of TV drama director Hong Yoon-Hee and surgeon Bang Gwi-Nam after they get married ...Yoon-Hee (Kim Nam-Joo) is a TV drama director. She recently married the perfect man for her. Yoon-Hee has been afraid of having in-laws, specifically a mother-in-law. Because of this, Yoon-Hee looked for a guy who isn't closely connected to his family. If she couldn't find such a guy, Yoon-Hee planned on staying single. Finally, Yoon-Hee met Terry (Yu Jun-Sang). Terry is a doctor with a sweet personality, but, most importantly, he has adopted parents from America. Terry has no recollections of his real parents and was adopted by the Korean couple in America as a young child. Yoon-Hee's marriage life seems all se

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.

Chun Ji Ae and Yang Bong Soon are high school classmates who did not have the best relationship with each other. Ji Ae was the most popular girl in school whereas Bong Soon was the girl that was always made fun of. Years later, their roles are reversed as Bong Soon's husband, Kang Joon Hyuk, is very successful whereas Ji Ae's husband, Ohn Dal Soo, is just an average company worker. Things get complicated when Dal Soo starts an extra-marital affair with his boss's wife, Eun So Hyuk. How will Ji Ae react to this?