At a difficult place in his marriage and career, a middle-aged man gets a shot at a do-over when he's transformed back into his 18-year-old body.

Ok Da-Jung is the youngest team leader in the cosmetics industry. She has divorced three times so far. She doesn't care what others think about her and she also has quite a temper. Nam Jung-Gi works as a section chief at the same cosmetics company as Ok Da-Jung. Unlike her, Nam Jung-Gi has a timid and nice personality. He can't say anything that makes others uncomfortable. He is able to make Ok Da-Jung's blood boil.

A wealthy man and a poor stunt girl fall in love. But things get complicated when their souls become inexplicably swapped and dark secrets surface.

Of the high-rolling top 'hot celebrities' of the wealthy upper class in Korea's high society, Kang Hye Na is the one desired by the men, feared and hated by the women. Being the only successor to the largest conglomerate company, Kang San Group, Kang Hye Na has both the looks and the background. She is the owner of the 'Lady Castle' and lives a 'princess-like' life with her servants.