Ji Yichen decided to leave home and travel to Korea alone for a Korean idol group. He studied abroad for five years and did not return home. An accident made Ji Yichen, a graduate and unemployed, become EXO's assistant. He had a series of stories with nine teenagers and saw their different sides in private and on stage. The bright sunshine, Sehun's thoughtfulness, Lay's sincerity, Baekhyun's cuteness, who do you like after spending a long time together? When Ji Yichen decided to leave his mother, what would happen to him and his mother?