Lee Changsoo is a bodyguard who faced disciplinary action and was removed from his position following an incident. Nevertheless, he is presented with an opportunity to regain his job if he successfully manages the company’s leading idol group, Luminous, on a temporary basis until a new manager is appointed. Changsoo coldly accepts this chance, yet he quickly discovers that the girls are resistant and potential sources of chaos at any given moment... Will Changsoo be able to return to his role as a bodyguard without any issues?