Kim Yu Ra is an ordinary senior high school student. She's going to be 18 years-old on March 13. She had a crush on her classmate, Park Seung Jo. She put a lot of efforts on it but he never realised. As the time went by, Yu Ra moved on from the guy. But then, her love story got more complicated.

She never noticed that at the other corner of the class, there's someone who always care for her...