It's a love story between the disobedient student Kang-uk and his teacher Yul-ju set in a high school in Chuncheon.
Before meeting Kang-uk, Yul-ju has been dating Tae-hyeon, a public prosecutor. But over time Yul-ju and Kang-uk fall deeply in love with each other despite social prejudices, the age gap and the teacher-student relation. One day, Yul-ju accidentally kills Kang-uk's classmate who intentionally harasses Kang-uk. But due to narcolepsy, Yul-ju doesn't remember what has happened, as she falls asleep during the incident. To protect her, Kang- uk goes to jail in place of Yul-ju.
Five years later, when Kang-uk is released from prison, he meets with Yul- ju again, but Yul-ju is engaged to Tae-hyeon. Learning what sacrifice he has made for her, Yul-ju wants to return to Kang-uk, but this time Kang-uk is not alone -- Ja-kyung, his former classmate and currently a radio program host, is beside him. The circumstances hamper Yul-ju from loving Kang-uk, but she is desperate to help him recover the lost five years and become a top-notch cook.