A cheerleading stunt gone wrong landed her in a 20-year coma. Now she's 37, newly awake and ready to live out her high school dream: becoming prom queen.
In 2002 and tells the story of Stephanie, the most popular girl in her high school. She's the captain of the cheerleading squad, dating the quarterback and is well on her way to becoming the prom queen. Girls want to be her and guys want to be with her. She has it all until she falls off the top of the cheerleading pyramid and goes into a coma. Fast forward 20 years later and Ruby finally wakes up from her coma as a 37-year-old woman. She goes back to her high school and tries to assume her role as the star of her school. Most of all, she is still set on winning the crown as prom queen.
In 1999, after a failed birthday party (the popular kids in school all give it a pass) at the local "cool" spot Rock N Bowl with her friends Seth (Sam Richardson) and Martha (Mary Holland), 14-year-old Australian immigrant Stephanie Conway (Rebel Wilson) decides she wants to be one of "the popular". She lives with her widowed dad Jim Conway (Chris Parnell).She spends the next few years giving herself a makeover, becoming cheer squad captain, dating popular boy Blaine (Justin Hartley) (who used to date a popular girl named Tiffany, who hated Stephanie), and becoming one of the most popular girls by senior year.
In 2002, Stephanie plans to win the title of prom queen in hopes of becoming like Deanna Russo (Alicia Silverstone), an alumna of her high school who seems to have the "perfect life" (has a banging bod, a rich husband, a picture-perfect house and no worries in life) (Stephanie believes it all started for Deanna with the prom queen title).
She lives with her widowed father and is still friends with Martha (who disapproves of how Blaine treats Stephanie) and Seth, who secretly has a crush on her. Stephanie has regular disagreements over prom preparations with Blaine's ex-girlfriend Tiffany (Zoë Chao), who feels threatened by the prospect of Stephanie winning the prom queen title. Tiffany hosts a parallel after prom-party and invites the entire football team over (including Blaine), to torpedo the party organized by Stephanie at Martha's grandfather's lake house.At a cheer performance, Tiffany convinces fellow cheerleaders to sabotage Stephanie's landing, severely injuring her and putting her into a coma.
20 years later in 2022, Stephanie wakes from her coma. Her father and Martha, Martha is now principal and cheer-leading coach at Harding High, take her home. On the way, driving past Deanna Russo's old house, Stephanie sees that the now-married Tiffany and Blaine (who is a Hummer salesman) reside there. With reluctant support from her father and Martha, Stephanie goes back to high school (Mr. T (Brandon Scott Jones) is the guidance counselor and gives Stephanie a tour of the "new" school), where she learns that Seth is now the librarian, and the prom queen contest has been abolished. Additionally, Tiffany and Blaine's daughter Bri (Jade Bender) is the most popular girl at school and has a huge social media following. The cheerleaders are no longer the popular kids and are not allowed to dance or perform suggestive routines.Stephanie makes friends with students & cheerleaders Janet Singh (Avantika Vandanapu), Neil Chudd (Jeremy Ray Taylor) and Yaz (Joshua Colley) (who is gay).
Stephanie works to regain her former popularity through social media, finally succeeding after a risque cheer routine she choreographs without Martha's permission goes viral. The next day, she is confronted by Martha, who tells her that she and Seth felt abandoned when Stephanie became popular back in high school. Martha says that she is gay, and this made high school a living hell for her.
Stephanie decides to attend a showing of Deep Impact with Seth (as Tiffany had posted on Insta that the Natural History Museum was offering 20% discounts and that she and Blaine were going to be there themselves), and they get closer after goading Tiffany into being thrown out of the showing. Afterwards, they go to the Rock N Bowl and Stephanie confesses that she wants to be elected prom queen so badly because she wants to make her mother proud.
Tiffany uses Bri's influence at school to get the prom king and queen contest reinstated (she tells Bri that she wants her to beat Stephanie at prom queen), and invites everyone at school except Stephanie to a prom after-party at their house (Steve Aoki is scheduled to DJ at the party). Stephanie decides to host her own after-party at Martha's family lake house without her knowledge. Seth agrees to go to prom with Stephanie but is hurt when he sees Blaine attempt to kiss her. Bri's boyfriend Lance (Michael Cimino) becomes prom king, and although Tiffany rigs the vote so Bri will win, Bri drops out so that Stephanie is the prom queen. Bri didn't like Tiffany trying to control her life and went against her.
As Stephanie and Lance share the prom king and queen dance, the school rallies around her. Bri tells everyone to attend Stephanie's after-party, which is successful until Tiffany gets the police to shut it down. Martha angrily confronts Stephanie for using her lake house without asking. On the way home from the party, Stephanie realizes her ride-share driver is Deanna Russo, who explains that being prom queen did not give her a perfect life and she is now struggling to make ends meet. Her husband divorced her before she was 30, for a 21 yr old. She had no credit and no job prospects. She regrets not going to college. She advises Stephanie to throw away the crown and focus on the future, instead of holding on to the past.
Bri arrives home, furious that Tiffany called the police on Stephanie's party, and points out that Tiffany didn't even ask if she was okay or if she had been arrested. Bri tells her mother that she knows she is in an unhappy marriage ruined by her desire to be popular and forces her to apologize to Stephanie. Stephanie accepts Tiffany's apology and encourages her to focus more on her daughter instead of keeping up appearances.
Stephanie contemplates not attending graduation, but her father convinces her to attend. Streaming an apology to her followers and friends, she promises to be her true self from now on. At graduation, her friends secretly organize the cheer routine from Stephanie's senior year. She makes up with Martha, finally kisses Seth, and welcomes Tiffany to join them on stage.