Katherine "Kat" Decker [Laura Marano] is a seventeen-year-old who dreams of becoming a famous singer‑songwriter. After the death of her father, Jason Decker, Kat is left in the custody of her cruel, snobbish stepmother, Deirdra Decker [Johannah Newmarch], and her two equally stern sisters, Joy Decker [Lillian Doucet-Roche] and Grace Decker [Chanelle Peloso]. They treat Kat as a servant, control her inheritance, and skim a large portion of her wages— supposedly to pay for her disabled dog Bruno [Capone]—leaving Kat determined to earn enough money to move out and chase her talents.
At "Santa Land," a Christmas‑themed park, Kat works as a singer and songwriter under the watchful eye of their strict boss, Mr. Mujiza [Garfield Wilson]. There they meet a teenage boy who is the new Santa—a young man named Nick Wintergarden, the secret son of billionaire Terrence Wintergarden. Nick is instantly drawn to Kat’s voice and sincerity, and he reveals that he manages a few bands, though he has never told his father about this side of his life.
Deirdre hatches a plan to secure invites to a charity event hosted by Terrence Wintergarden, using the ruse that she is the widow of Kat’s late father. The scheme depends on Joy impersonating Kat to slip into the event while the real Kat stays home. But a letter from Terrence invites Deirdre and Kat to attend, complicating the deception and setting the stage for a confrontation with the truth.
As Christmas Eve draws near, Kat and Nick grow closer. Nick gives Kat an invitation to the Wintergarden charity event, and she accepts with a mix of excitement and nerves. The next day, Nick reveals his true identity to Kat, who is reluctant to reveal hers in return. Isla [Isabella Gómez] helps by sewing a green dress that Kat can wear to pass as one of the elf performers, showing how friendship can bridge gaps even when secrets loom.
Trouble erupts when Deirdre and the stepsisters steal Kat’s dress and Deirdre burns the invitation. Bruno discovers the snow globe from Kat’s late father, a moment that underscores what is at stake. Realizing their plan to steal Kat’s identity, she resolves to fight back. Isla uses her access as the show’s dressmaker to help Kat slip in as an elf performer, but the moment Kat steps on stage, Deirdre and Nick spot her, and Skylar tries to lure Nick away, only to be turned down.
During the charity show, Kat is pressed into the Snow Queen role after a performer is knocked out, and she delivers a stirring performance of a song she wrote herself. The moment marks a turning point: Kat’s voice shines, Nick apologizes for hurting her, and she forgives him as they reconnect in the glow of the audience. Nick encourages Kat to chase her dreams for her father, and she delivers a powerful finale that wins over everyone watching.
After the show, Terrence meets Kat and, moved by her story and financial need, offers to help as a last wish for his late friend. He orders Deirdre, Joy, and Grace to leave, clearing the way for Kat’s future. In the final scene, Kat and Nick share a hopeful dance, symbolizing the beginning of a new chapter where her dream feels achievable and real.
