It's a love story between the disobedient student Kang-wook and his teacher Yool-ju set in a high school in Chuncheon.

Before meeting Kang-wook, Yool-ju has been dating Tae-hyeon, a public prosecutor. But over time Yool-ju and Kang-wook fall deeply in love with each other despite social prejudices, the age gap and the teacher-student relation. One day, Yool-ju accidentally kills Kang-wook's classmate who intentionally harasses Kang-wook. But due to narcolepsy, Yool-ju doesn't remember what has happened, as she falls asleep during the incident. To protect her, Kang-wook goes to jail in place of Yool-ju.

Five years later, when Kang-wook is released from prison, he meets with Yool-ju again, but Yool-ju is engaged to Tae-hyeon. Learning what sacrifice he has made for her, Yool-ju wants to return to Kang-wook, but this time Kang-wook is not alone -- Ja-kyung, his former classmate and currently a radio program host, is beside him. The circumstances hamper Yool-ju from loving Kang-wook, but she is desperate to help him recover the lost five years and become a top-notch cook.

Source: KBS Global Marketing

This drama is about the lives of Tae-hee and Yun-hee, two sisters whose mother died while giving birth to Yun-hee. Their father, who loves them dearly, married their mother without their paternal grandfather's consent, and deprived of any familial support, the sisters and their father struggle to make ends meet even as their father faces a life-threatening illness. This drama follows Tae-hee and Yun-hee into adulthood as, separated by a cruel twist of fate, the girls come to lead very different lives, oblivious of one another.