Lee Young-Joon's family runs a large company and he works as the vice-president of the company. He is smart, rich and handsome, but he is arrogant. His secretary is Kim Mi-So. She has worked for him for years and she is perfect for him, but Kim Mi-So decides to quit her job.

A woman with a gift for lying is employed by a chaebol heir to act as his long-lost cousin. To keep up the charade for his family, the two must live under the same roof, but their growing attraction to each other poses a problem for pretending to be relatives.