My Madam was my Teacher

Junghoon has a crush on his high school teacher, Jieun. She is his first love. One day, Junghoon finds out his teacher is going to get married. Rumors starts to fly that Jieun married a rich man and that she was a concubine. Devastated, Junghoon lost his feelings for his first love.
Years later, Junghoon is still unemployed and lived a life doing one night stands with other women. Felt with pity for his life, Junghoon's friend introduced him to a job opportunity in becoming a driver to a rich household.
During his interview, Junghoon meets his first love, Jieun, now as the mistress of the mansion.