From Esthétique:

A teacher's pet and a model student, Young-Won Lee, at this important time right before the college entrance exam, feels her heart beating faster toward a delinquent… When she can't get a reasonable answer from books, she follows the philosophy that after being lovers for 3 months, the love hormone that confuses the lover disappears. Thus, she decides to show her interest to the delinquent-!! What did you say? You hate nerds like me? Just wait, Haru Kang! I'll become a hot, flashy babe and make you fall for me!