Park Chanyeol and Do Kyungsoo well known as the 'inseparable glue' by their classmates during their middle school. Everything went well until Chanyeol had to leave his hometown and went to Seoul due to parent's work. Kyungsoo? He lives with his single mother. They had promised each other that they will reunited again in high school. 

Kyungsoo is smart and Chanyeol acknowledged it. Fortunately, after few years separated, Kyungsoo got a scholarship to enter the most prestigious all boys boarding school and met his best friend again. And at the same time, he met Kim Jongin, an arrogant who uses his money and power to shut people's mouth and unexpectedly, his roommate.