该剧以一起发生在校园里的杀人案为背景，讲述了家境平凡的转学生作为唯一的目击者与身为最大嫌疑人的财阀三世相遇上演心理战的故事。

在一所貴族高中目睹謀殺事件之後，來自低收入戶家庭的女孩得到入學就讀的機會，不過條件是她得保密一切。

Kim Hye-in is a high school student from a poor background. She becomes the only witness to the murder of a high school girl. In exchange for her silence on the murder she witnessed, she is offered a chance to study at Cheongdam International High School, the most prestigious high school. There, Kim Hye-in meets Baek Je-na, the leading suspect of the murder and the most powerful student at Cheongdam High. They engage in psychological warfare full of tension and a fierce power struggle.

모두가 선망하는 상위 1% 귀족학교 청담국제고에서 일어난 여고생 살인사건. 유일한 목격자이자 흙수저 전학생 혜인과 유력한 용의자이자 이 학교의 여왕, 최고 권력자인 제나가 자신의 것을 지키기 위해 부딪히는 하이틴 심리 스릴러

หลังไปเห็นการฆาตกรรมที่โรงเรียนมัธยมปลายชั้นนำ เด็กสาวจากครอบครัวยากจนก็ได้รับโอกาสให้เข้าเรียนในโรงเรียนนั้น แต่ต้องเก็บสิ่งที่เธอเห็นไว้เป็นความลับ