Hanna Kang is an overweight phone-sex worker who also serves as a ghost singer for Ammy, a famous pop star who lip-syncs her songs. Hanna harbors a crush on Sang-jun Han, a director whose arrogant father, President Choi, runs the record label that Ammy is signed to. One day, Ammy sends Hanna an outfit she claims is from Sang-jun to wear to his birthday party, and then wears the same outfit at the party herself to publicly humiliate Hanna. Crying in the restroom, Hanna overhears Sang-jun telling Ammy to be kind to her so she can continue using Hanna’s voice. Devastated, Hanna attempts suicide, but a phone call from one of her clients, a plastic surgeon, halts the act and leads to extensive surgery that changes everything.
A year later, Hanna emerges transformed—slim and stunning enough that even her best friend Park Jeong-min barely recognizes her at first. With Park Jeong-min’s help, Hanna reinvent herself as a Korean-American from California named Jenny. After re-auditioning to become Ammy’s secret vocalist, she earns her own recording contract and steps into the spotlight on her own terms. Yet Ammy grows anxious that her own inability to sing could be exposed if the release of the second album is delayed. In a bid to locate Hanna, Ammy spends time with Hanna’s father, who is coping with Alzheimer’s, but Sang-jun orders her to stop, threatening to terminate her contract if she persists. Through many encounters with Jenny, the truth finally surfaces: Jenny is Hanna.
Jenny’s debut single, “Maria,” shoots to the top and during the release party Ammy brings Hanna’s father in an attempt to blow her cover. Hanna, furious and feeling betrayed, withdraws from her father, which only fuels Jung-min’s frustration. After the party, Sang-jun confesses that he knows who she really is and struggles to forgive the deception. Hanna then reveals the extent of her surgery and her willingness to change everything to win his love. Yet, she also questions whether she can ever be loved for who she truly is. In a pivotal moment, she decides that she must live for herself, not for a man or a label.
The following day, Ammy threatens to reveal Hanna’s deception unless Sang-jun cancels the concert. Choi agrees with Ammy, but Sang-jun stands firm, encouraging Hanna to perform for herself rather than for anyone else. Before going on stage, Hanna apologizes to Jung-min for her past behavior, though Jung-min rebukes her for how she treated her own father. On stage, Hanna makes a moving confession to the audience: she was the ghost singer behind Ammy during her overweight years, and she underwent extensive plastic surgery, sacrificing friends and family for her career. Sang-jun plays a tape of the old, heavier Hanna singing, which Hanna insists is the real her. The crowd responds with empathy and admiration for her honesty.
In the end, Hanna reconciles with her father and with Jung-min, sheds the alias Jenny, and becomes a successful artist in her own name. Sang-jun realizes he has always been in love with Hanna and continues to promote her, hoping to pursue a relationship with her. The film closes on a note of resilience and self-acceptance, as Hanna embraces her authentic self and the people who stood by her.
