The story begins when Joon-sang, the son of an eminent musician, moves to Chuncheon, a rural city in South Korea. As an extraordinarily talented student, Joon-sang is welcomed by his fellow students as well as his teachers, but remains a quiet, introverted teenager. As a result of the belief that his biological father is dead, and serious disagreements with his mother, Joon-sang believes that no one truly loves him.
On his way to school one day, Joon-sang's classmate Yoo-jin, while sitting next to him on the bus, falls asleep on his shoulder. Joon-sang soon falls in love with Yoo-jin, who opens her innocent heart to him. Their love, however, is cut short after Joon-sang is badly injured in a car accident and, due to brain damage, suffers from amnesia, unable to remember anything prior to his accident.
Joon-sang's mother, yearning for Joon-sang's love and respect, has Joon-sang brainwashed by a psychologist, so that Joon-sang will not remember his painful childhood as an illegitimate child. As a result, Joon-sang's memories prior to the accident are erased. Joon-sang's mother decides to move to the United States with Joon-sang, where he can start a new life under the identity of Lee Min-hyung. His friends and teachers are told that Joon-sang is dead.
Ten years later, Min-hyung is an award-winning architect in the United States. He does not remember anything about his life in Korea. He is completely different, now an open-minded person who cares about other people. He returns to Korea and Yoo-jin sees him on the street, prompting her to put off her engagement to her childhood friend Sang-hyuk. Little does she know that Min-hyung is dating her friend and past rival Chae-rin. The story's plot thickens when Yoo-jin's interior design firm is awarded a project by Min-hyung's architectural firm, and has to work with Min-hyung. Yoo-jin sometimes wonders if he is her supposedly dead first love Joon-sang.