On the first day of attending his new high school, Park Sae Ro Yi punches his classmate Jang Geun Won, who was bullying another classmate. The bully is the son of CEO Jang Dae Hee. The bully's father runs restaurant business Jagga where Park Sae Ro Yi’s own father works. CEO Jang Dae Hee demands to Park Sae Ro Yi that he apologizes to his son, but Park Sae Ro Yi refuses. Because of his refusal, Park Sae Ro Yi gets expelled from school and his father gets fired from his job. Soon, an accident takes place. Park Sae Ro Yi’s father dies in a motorcycle accident caused by his ex-classmate Jang Geun Won. Burning with anger, Park Sae Ro Yi viciously beats Jang Geun Won. He is soon arrested and receives prison time for violent assault. Park Sae Ro Yi decides to destroy the Jagga company and take revenge upon CEO Jang Dae Hee and his son Jang Geun Won. Once Park Sae Ro Yi is released from prison, he opens a restaurant in Itaewon, Seoul. Jo Yi Seo, who is popular on social media, joins Park Sae Ro Yi’s restaurant and works there as a manager. She has feelings for Park Sae Ro Yi. Adapted from the webtoon "Itaewon Class" (이태원 클라쓰) by Jo Gwang Jin (조광진).