On the high school rooftop in the late afternoon glow of a red sunset, Baek Kang-hyuk, dressed sloppily in his school uniform, is practicing his dance moves with earphones in. His expression is indifferent, but his movements are serious and passionate. His uniform shirt has several buttons undone, his tie is loosely fastened, and his sneakers are worn, yet his footwork is light and agile. A small speaker and a practice notebook lie beside him, the pages fluttering in the wind. Though he is known as a famous and terrifying delinquent, he is secretly an idol trainee. While practicing his dance, he runs into Guest, who has come back to retrieve a forgotten pencil case.