After years of unemployment and failure, Kang Da-hye suddenly regresses to her second year of high school. Determined to rewrite her life, she vows to ace the college entrance exam, get into Korea University, and secure a successful career.

But her plans for a romance-free future are ruined when two handsome boys enter her life. Jung Eun-sung, a future idol star who also regressed, and Seo Jae-gyeom, her former crush and the illegitimate heir of a wealthy family, both begin pursuing her.

With love confessions coming from every direction, Da-hye has only one thing on her mind: studying!