Yeon Yi-Sol, the top student whose true feelings became visible through hashtags. But then her first love, Seong Shin-U, tagged her as ‘#TheTrashWhoWasMyFirstLove’?! Without knowing why, the pain of being abandoned resurfaces, and Yi-Sol teams up with Baek Seol, who hates Shin-U.
Is it revenge? Or lingering feelings? This time, who will be hurt first?