Choi Han-gyul (Gong Yoo) is the grandson of chairwoman Bang (Kim Young-ok) of Dong-in Foods, a company that has a thriving coffee business. He has never had a job and does not care for responsibility. Han-gyul is hung up on his first love, Han Yoo-joo (Chae Jung-an), who only sees him as a friend. Go Eun-chan (Yoon Eun-hye) is a 24-year-old tomboy who is often mistaken for a guy. Her father died when she was 16 years old and since then she has taken over as the breadwinner in her family. When Han-kyul and Eun-chan meet, he, not knowing that she is a girl, decides to hire her to pretend to be his gay lover so that he can escape the blind dates arranged by his grandmother.
After getting an ultimatum from his grandmother, Han-gyul takes over a rundown old coffee shop, later renamed “Coffee Prince,” to prove that he’s capable, both to his grandmother and to Yoo-joo. In order to attract female customers, he only hires good-looking male employees. Eun-chan, desperate for money, continues to hide her gender to get a job at Coffee Prince.
Soon, feelings start to develop between Eun-chan and Han-kyul. As Han-gyul is unaware that Eun-chan is a woman, he starts to question his sexuality and is thrown into turmoil. When Han-gyul finds out that Eun-chan is a woman, he gets angry. But soon, they make amends with each other and the two fall in love again. Eun-chan eventually leaves for Italy to study and Han-gyul supports her.