The film begins with Carpenter walking onstage to sing "Buy Me Presents" on a multiple-tiered stage resembling a
birthday cake. After the performance, Carpenter sings "It's the Most Nonsense Time of the Year" — "
It's the Most Wonderful Time of the Year" with alternate lyrics — while walking backstage. Carpenter and
Tyla then duet to "
This Christmas" in the living room. Afterward, Carpenter sings "Santa Doesn't Know You Like I Do" solo onstage, while videos of her opening Christmas presents in 2002 play in the background. Next, Carpenter is shown in the living room with two friends, played by
Owen Thiele and
Megan Stalter. Carpenter tells them about her new boyfriend, who then appears and Thiele and Stalter recognize as
Santa Claus (
Sean Astin). However, Carpenter sincerely denies this, adding that he is "good in bed". When Thiele and Stalter persist with their argument, Carpenter says that if he were really Santa Claus, he would know that all she had ever wanted since she was a child was to sing a duet with
Shania Twain. At that moment, Twain arrives, but is revealed to be
Mrs. Claus. She and Twain then sing "
Santa Baby" onstage together. Thiele then proposes alternate lyrics to Carpenter's song "
Nonsense", which are considerably cheesy. Carpenter tries to be polite, but is visibly opposed to the proposed lyrics. The following scene shows Carpenter back in the living room, surrounded by family members, including Sabrina's sister Amy (
Jillian Bell) and brother-in-law Dave (
Kyle Mooney). Carpenter sings "What Do I Get My Brother-In-Law" while hopelessly trying to figure out a gift to give Dave. In the next scene, Carpenter and
Kali Uchis sing "
I Saw Mommy Kissing Santa Claus" in front of the living room fireplace. Next,
Ebby Scrooge (
Nico Hiraga) falls asleep on the living room couch and is haunted by the
Spirit of Ghosted Past (Carpenter), who chastises him for ghosting her. The
Spirit of Ghosted Present (
Quinta Brunson) appears next to her and angrily asks why Scrooge disappeared instead of taking her to see
Wicked in the theater like he promised. Then the
Spirit of Ghosted Future (
Cara Delevingne) appears and begins to fall for Scrooge. However, the other two ghosts warn her that he will ghost her should they begin a relationship, persuading her to leave him alone. Before leaving, Delevingne proposes alternate lyrics to "Nonsense", which are considerably better than Thiele's. Carpenter and
Chappell Roan sing
karaoke to "
Last Christmas" in the living room. Carpenter then sings "Cindy Lou Who" on the piano. Before ending the film, Carpenter returns to the birthday cake stage, now with a staircase in the middle, and performs "
A Nonsense Christmas". == Musical numbers ==