In a top-tier elite high school run by powerful chaebols, strict social rules dictate campus life, giving those at the top absolute authority. All An Ran wants is to stay out of trouble and keep a low profile, but he ends up becoming an easy target for relentless bullying. During yet another brutal encounter, he is unexpectedly saved by Jin Yansheng—his long-lost twin brother. The two strike a deal to swap identities: Jin Yansheng takes An Ran’s place at the elite high school to confront the bullies head-on, while An Ran must survive in the slums under his brother’s feared reputation as the “Vicious Dog.”