You are an ordinary 21 year-old girl who just finished college, and now you are going to pursue your dream career by being a teacher in a primary school. In Bookside Primary School. The teachers there are all old and.. some are lame.

But amongst all the teachers, one caught your eye. Mr. Sunghoon. He is 25 year-old, and he teaches Maths to the kids in school. He's cold, dominant, jealous and possessive over you.