"Himegimi no Icon" centers on the life of Himeko, a high school girl who unexpectedly becomes the face of a popular idol group despite her lack of interest in the entertainment industry. Himeko is thrust into the spotlight when she is scouted by a talent agency due to her striking resemblance to a former idol who mysteriously disappeared. Reluctantly, she agrees to take on the role, adopting the stage name "Himegimi," and quickly gains fame for her beauty and enigmatic persona. However, Himeko struggles with the pressures of fame, the expectations of her fans, and the demands of her agency, all while trying to maintain her true identity and personal life.

The narrative explores the duality of Himeko's existence, contrasting her public persona as the glamorous "Himegimi" with her private self, a reserved and introspective girl who values authenticity. As she navigates the cutthroat world of idol culture, Himeko forms complex relationships with her fellow group members, each of whom has their own motivations and struggles. The story delves into themes of identity, self-discovery, and the cost of fame, as Himeko grapples with the question of whether she can remain true to herself while fulfilling the role of an idol.

Key characters include Himeko's manager, who serves as both a mentor and a source of conflict, pushing her to conform to industry standards, and her rival within the group, who views Himeko as a threat to her own career. The series also introduces a childhood friend who re-enters Himeko's life, offering a connection to her past and a reminder of the person she was before becoming an idol. Through these relationships, the story examines the tension between personal desires and professional obligations, as well as the sacrifices required to succeed in the entertainment industry. The plot unfolds with a mix of drama, introspection, and moments of levity, providing a nuanced portrayal of the challenges faced by those in the public eye.