Story
When Min Gun Lee is rejected after confessing to the upperclassman he likes, he is shocked when his crush's scary twin brother Jo Gan immediately asks him out afterward... and refuses to take no for an answer! With the nickname "Mad Dog" and a reputation for putting a teacher in the hospital, Jo Gan is the very picture of a juvenile delinquent - the exact opposite of his princely, model student brother Jo Han.
Synopsis via AniList (English).