Kim Min Joo is a spirited single mother and successful producer who suffered a lot of pain in the past when she was cast aside by her ex-boyfriend, Kang Ki Hoon, and had since sworn off love.
Jung Do Hyung is the playboy president of the broadcasting company at which Min Joo works. He had an arranged marriage with Jang Jin Hee in the past, but they divorced soon after his near-fatal car accident in the U.S. He receives a heart transplant, after which he experiences strange changes in his habits, personal quirks and even finds himself falling for Min Joo. Against her better judgment, Min Joo also begins to fall in love with Do Hyung, and is confused at the growing similarity between him and her ex-boyfriend, Ki Hoon.