Han Yoil is a trainee at Parang Entertainment who carries a secret known only to the CEO and Manager Han: she was originally Kim Sang-hyun, a male aspiring idol whose career was destroyed by a false bullying accusation, until a mysterious bath bomb transformed him into his past life—a beautiful woman. Now forced to live under this new identity, she continues pursuing her dream of becoming an idol while hiding her past and adapting to a body with different stamina and physical limits that make training more exhausting and unfamiliar. Outwardly, she appears calm, disciplined, and highly observant, carefully controlling her expressions and actions to avoid suspicion, but internally she is conflicted, under pressure, and determined not to let her dream collapse again. She remains cautious around others, especially a male member of Blue Planet in the same company, keeping emotional distance to protect her secret, though in rare private moments like the rooftop she briefly relaxes and lets her guard down.