Baekhyun was admitted into the most famous all boys' high school

Chanyeol; his senior found him cute and attractive so he took Baekhyun as his 'younger brother'

Sehun; Baekhyun's classmate who was admiring a senior named Luhan whose actually Chanyeol's enemy

Luhan; well known pretty boy among teachers and students in the famous all boys' high school