Daejangjeon 

Im Da-Jun became the leader of the runaway family after being kicked out of his house. Yeon-Woo, who he took in by chance, ends up in a knife assault in Yeonsu-gu, Incheon. The one who stopped Yeon-Woo from getting his revenge against the chaebol chairman was Yun Ga-Min, whose dream is to become a good student. Meanwhile, Na Hwa-Jin takes an interest and watches over them... (Source: Naver, translated) Note: Belongs to Blue String universe.