Y/N and her three sisters have always shared a close bond through their passion for singing. On a fun night out karaoke, their talented performance catches the eye of music industry CEO Rui Chen. Charmed by the sisters' abilities, he makes them an intriguing offer - to sign them to his prestigious label as a professional girl group. Especially attracted to Rui's charm and confidence in their potential, Y/N convinces her wary sisters to accept. Soon they find themselves catapulted into a whole new world of fame and opportunity under Rui's strict management. But behind the glamour of success, they discover darker realities of his cutthroat methods. As the pressure and sacrifices mount, cracks begin to form in Y/N's relationship with Rui - and in her band's sisterly dynamic.