Kim Min Seon plays the beautiful Lee Yul Ju, the teacher who breaks every rule in the book by falling in love with her student. A warm-hearted, optimistic and respected young woman, Yul Ju shrugs off the social prejudices that arise as a result of her relationship. But then, Yul Ju has always been a fighter - she has had to deal with narcolepsy her whole life.

Tragedy strikes the young couple when Yul Ju accidentally causes the death of one of Kang Uk's classmates. However, Yul Ju also suffers a seizure and forgets the incident ever occured. To protect the woman he loves, Kang Uk takes the blame for the boy's death and is sentenced to five years in prison.

On his release, Kang Uk is determined to rebuild his relationship with Yul Ju, but he discovers that she is now engaged to somebody else...