Kkumeseo Jayuro

Jeong-Min is a loner in high school being bullied by the Queen Bee, Ju-Hyeon. The two were friends in elementary school before their friendship ended because of Ju-Hyeon’s demand that Jeong-Min should only be friends with her. Ju-Hyeon uses this “betrayal” to fuel the classmates' insults and isolate Jeong-Min in misery. Jeong-Min has only one way to escape, through lucid dreams. One day, a mysterious man enters her dreams and offers to help her get revenge on Ju-Hyeon…

(Source: WEBTOONS, edited)

Note: The chapter count includes 13 extra chapters.