After a tragic car accident, 18-year-old Kang Gyung Joon discovers that his spirit has been transported to the body of 30-year-old Seo Yoon Jae. Yoon Jae is a successful doctor who is engaged to high school teacher Gil Da Ran. But Da Ran just so happens to be Gyung Joon’s teacher. What is a boy to do when he discovers that he has become his own teacher’s fiancé by a freak of nature? Will he be able to return to his own normal life or is he doomed to live out the older man’s instead?

The background of the drama is about life in the mergers & acquisitions, stock market and financial world, as well as the lives of chaebols.

Lee Min Jung is a the daughter of a chaebol family, however, their financial status declines and they are forced to move in with their longtime chauffeur's (Choi Bool Am) family. The once rich and spoiled daughter must learn how to adapt and live as a commoner.