The new story follows Stargirl's journey out of Mica and into a bigger world of music, dreams and possibility.
Having moved away from Mica, Stargirl and her mother Ana arrive in Los Angeles to start a new life. Ana has gotten a job as a costume designer for a feature film, but the director is notoriously difficult to work with. While strumming in her room, Stargirl meets Evan, the son of the building tenants, who tells her that he and his brother Terrell are making a sizzle reel for a potential film and would like her to make the music and possibly act in the film. While Stargirl has never acted before, she is convinced by the brothers and visits Terrell's workplace; a bar called Forte. One of the usual visitors, known to Terrell as "Table Six", is actually Roxanne Martel, a one-hit wonder who left the music scene early, became a producer and is the actual owner of Forte.
Ana continues to get called into work; leaving Stargirl to her own devices. Among the things she does is buy a pair of headphones for her grumpy neighbor Mr. Mitchell, who slowly begins to open up and reveal that he was once a film producer. Stargirl also meets with Roxanne to ask if she could use her song "Miracle Mile" for their sizzle reel, but she refuses; giving the impression that she is anti-social and bitter. Stargirl and Evan get the idea to write their own song called "Figure It Out", to which Roxanne reveals that she denied them use of her song so that they can create their own. Afterwards, she allows them to use a professional studio to record. As the song gets incorporated into the film, Stargirl and Evan begin a relationship with one another; similar to the leads in the film, which Stargirl finds similarities between herself and Leo.
Stargirl, Evan and Terrell finish the sizzle reel and send it out. As they wait for a response, Stargirl relates her past to Evan. Terrell eventually gets the news that an executive named Priya Collins has picked up the sizzle reel. She offers them a budget of one million dollars; enough to shoot their film. As Stargirl returns home, she is hit with news from Ana that the film's production has shut down due to the director's behavior and that she has already accepted another job in Berkley. Stargirl is angered at the news as she has started to love living in Los Angeles and realizes that much of Ana's issues are stemmed from her fear of staying in one place. Stargirl talks with Terrell and Mr. Mitchell, the latter of whom gives her advice that one should learn from their mistakes and was inspired by her to talk to his son again.
Stargirl finally talks with Ana and convinces her that they should stay and that she needs to accept the mistakes in life. While at Forte, Evan and Terrell are shocked to see Stargirl with Roxanne in a new music group called Table Six and the Shirley Temples. Stargirl reveals that she loves Los Angeles too much and that she will be staying after all as a newly supportive Ana watches. The group play a rendition of "Dreaming" as everyone celebrates. Sometime later, Terrell has started filming his new movie Tell Your Story with Evan and Stargirl in the leads.
- Grace VanderWaal as Stargirl Caraway
- Elijah Richardson as Evan
- Judy Greer as Ana Caraway
- Uma Thurman as Roxanne Martel
- Judd Hirsch as Mr. Mitchell
- Tyrel Jackson Williams as Terrell
- Al Madrigal as Iggy
- Sarayu Blue as Priya Collins
- Chris Williams as George, Evan and Terrell's father
- Nija Okoro as Daphne, Evan and Terrell's mother
- Ben Geurens as Daniel
- Noah Taliferro as Mike
- "Just What I Needed" by The Cars
- "Everywhere" by Fleetwood Mac
- "Make Your Own Kind of Music" by Grace Vanderwaal (Stargirl)
- "1% Crown" by Scone Cash Players
- "No Myth" by Jasmine Ash and Peter Adams
- "Love and Mercy" by Grace Vanderwaal (Stargirl) and The Beach Boys
- "Miracle Mile" by Z Berg (as Roxanne Martel)
- "Figure It Out" by Grace Vanderwaal (Stargirl) and Elijah Richardson (Evan)
- "One Woman" by STACEY
- "If I Got It (Your Love Brought It)" by Aaron Frazer
- "Biggest Gossip In Town" by Rockin Horse
- "Glory Strums (Loneliness of the Long Distance Runner)" by Hiss Golden Messenger
- "Dreaming" by Grace Vanderwaal (Stargirl) and Uma Thurman (Roxanne Martel)
- "Heaven Knows" by Grace Vanderwaal (Stargirl)
In February 2021, the sequel was announced and have Judy Greer and Elijah Richardson joined the cast with Grace VanderWaal. In April 2021, many cast joins in. On May 17, 2021, the production begins. Then two months later on July 7, 2021, the production wraps.
- There is a sequel novel to Stargirl called Love, Stargirl which tells of Stargirl immediately following the events of the first book. The movie however, follows a completely different story.