Plot
In Edgewater, Indiana, James Madison High School's head of the PTA, Mrs. Greene, announces the cancellation of prom because lesbian student Emma Nolan planned to attend with her girlfriend Alyssa, Mrs. Greene's closeted daughter. Principal Tom Hawkins supports Emma, but is powerless against the PTA's decision.
Broadway stars Dee Dee Allen and Barry Glickman are disappointed after their show Eleanor! The Eleanor Roosevelt Story closes on opening night following a negative review by The New York Times. They are comforted by Trent Oliver, a faded sitcom star reduced to forgettable theatre work, and Angie Dickinson, who just quit the chorus line of Chicago after being passed over for the role of Roxie Hart. Barry realizes they all need a cause to revitalize their careers. Finding Emma's story on Twitter inspires the actors to drive to Indiana with the non-Equity touring cast of Godspell and publicist Sheldon Saperstein.
Emma is bullied and harassed at school by Kaylee, Shelby, Nick and Kevin, who blame her for ruining prom. The actors barge into the next PTA meeting and attempt to rally support for Emma. Principal Hawkins, a fan of Dee Dee's, fails to convince her to back off. The actors book themselves as entertainment for a monster truck rally, but are booed off the stage for preaching about acceptance. Hawkins tells them the Indiana Supreme Court has ruled the school must allow Emma to attend prom and later bonds with Dee Dee over dinner.
On promposal day, Barry visits Emma at her grandmother Bea's where she's been living since her sixteenth birthday, after her parents threw her out for being gay. Barry tells Emma he ran away from home at sixteen because he knew his parents wouldn't accept his sexual orientation.
The PTA exploits a loophole in the Court's ruling by arranging a separate prom for Emma to attend alone while hosting the rest of the students at a private club. Emma calls Alyssa for support, however she is too scared of losing her mother to come out. Hawkins is disgusted when he learns the real reason that Dee Dee came to Indiana was to use Emma to prop up her career.
Mrs. Greene holds a press conference about the two proms. Angie comforts a heartbroken Emma. When Barry persuades Dee Dee to get Emma on her ex-husband Eddie Sharp's talk show, she insists that he call his estranged mother Vera and make peace. Dee Dee apologizes to Hawkins for lying to him and they reconcile. Emma, upset that Alyssa won't stand up to her mother, breaks up with her.
Trent confronts Emma's tormentors, persuading them to support her with help from the Godspell cast. Dee Dee arrives at the motel and announces she traded Eddie her house in The Hamptons for Emma's slot on his show but Emma turns the offer down to tell her story her own way. She sings a song she wrote during a livestream, which goes viral.
The actors pool their finances to throw an all-inclusive prom for Emma. Afterward, Dee Dee tells Barry she called Vera, who wants to talk to him. Vera apologizes to Barry for her past treatment of him, so they make peace.
Kaylee, Shelby, Nick and Kevin apologize to Alyssa and Emma for their behavior. Mrs. Greene tries to stop their preparations for the prom. When Alyssa reveals who she really is, her mother leaves. Alyssa and Emma reconcile.
Emma and Alyssa arrive early to meet with the actors, Sheldon, Bea, and Vera. Angie learns that she has been cast as Roxie Hart as Tina Louise has contracted shingles, Trent retires from acting to become the school's new drama teacher, and Barry is crowned prom king. The students and many teens from the local LGBT community show up to the prom in support of Emma. As the event begins, Mrs. Greene apologizes, and embraces Alyssa, accepting her for who she is. Dee Dee and Principal Hawkins kiss and start a relationship. Emma and Alyssa share their first public kiss as everyone celebrates.