Taesan is a member of Rookie boygroup BOYNEXTDOOR along with Woonhak, Leehan, Riwoo, Jaehyun, Sungho. He is the Rapper and center of the group. Even though for outside world he was the cool guy, he was broken from inside.

He used have a girlfriend in Highschool, Minji from New Jeans. She's also a kpop idol. She cheated on him with a old rich producer for money and fame.

One night Taesan was sitting in the car with other BOYNEXTDOOR members, heading to dorm after schedule, it was drizzling night making the night more beautiful, The car stopped in red light, His eyes fell on a bus, a girl by the window of the bus.