The film did not receive advance screenings upon its release, and fared weakly among critics. It grossed almost $5 million at the United States box office, after opening with $1.8 million. It was released on VHS in 1986 and on DVD in 2004.
When Rainbow Brite (Bettina Bush) and her magical horse, Starlite (Andre Stojka), go to Earth to start spring, they meet Stormy (Marissa Mendenhall), another magical girl who controls winter with her horse, Skydancer (Peter Cullen). She, however, doesn't want to end her winter fun, so Rainbow battles her for control over the season. She proves to be no match for Rainbow and Starlite, who outrun her and head off to Earth. When they arrive, they meet up with Brian (Scott Menville), the only boy on Earth who can "see" them.
Once Rainbow tries to start spring, however, her power weakens and winter remains. Brian becomes worried that spring will never come and senses that all of humanity is losing hope. Even Stormy is confused. Reassuring Brian that they will do what they can to return spring, Rainbow and Starlite return to Rainbowland.
Rainbow is paid a visit by On-X (Pat Fraley), a strange robotic horse with rockets for legs.
Rainbow takes the mission to find Orin and later learns that Spectra is dimming as the result of a massive net being woven around the surface. It is being made so that a selfish princess (Rhonda Aldrich), known only as the "Dark Princess", can steal Spectra, "the greatest diamond in all the universe", for herself, and tow it back to her world with her massive spaceship. The native Sprites of Spectra, enslaved by Glitterbots under the princess' control, are being forced to weave the net. Now Rainbow has to stop the princess' plan before all life on Earth is frozen solid by an endless winter.
Helping Rainbow and Starlite is Krys (David Mendenhall), a boy from Spectra. He believes he can take on the princess and save his home world by himself without the help of a "dumb girl". When they meet Orin, he tries to make them get along and work together to stop the princess. He tells them that they can only destroy her by combining their own powers against her.
Getting in the way of their mission is the sinister Murky Dismal (Peter Cullen) and his bumbling assistant, Lurky (Pat Fraley), who, as usual, are lavishing in the new gloom created by the darkening of Spectra, as well as trying to steal Rainbow's magical color belt.
After dodging Murky, Rainbow and Krys enter the princess' castle and try to convince her that what she is doing will destroy the universe, but she is determined to have Spectra for herself and traps them instead.
The enslaved Sprites are freed and immediately destroy the net so that Spectra radiates its magical light once again. On Earth, a warm spring finally arrives as life returns there and Rainbow returns to Rainbowland, finding her friends are back to normal.
The film was the second feature film made by DIC Enterprises, who had earlier success with their first TV shows, Inspector Gadget and The Littles. DIC was hired by Hallmark Cards to produce the first three syndicated specials centering on Rainbow Brite. Their success led to the production of a feature movie based on the toy.
The project was directed by French animator Bernard Deyriès, well-known at the time for DIC's science-fiction series Ulysses 31 and Mysterious Cities of Gold (both also animated by Japanese studios), and Japanese partner Kimio Yabuki, a legendary animator at Toei Animation and former cohort of Hayao Miyazaki. The film's art director, Rich Rudish, had been a staff member of Hallmark since 1964.
The music was composed by Haim Saban and Shuki Levy, who produced various music for cartoons in the 80s and would go on to launch the Power Rangers series in the 1990s. Story co-writer Howard Cohen wrote the film's bookending songs, "Brand New Day" and "Rainbow Brite and Me".
The film was produced in only three months, at that time the quickest on record for an animated feature. While the U.S. unit contributed to the film's production, some Japanese companies took on animation outsourcing duties (as was often the case with DIC's productions of the time), among them Cockpit, Zaendou, Doga-Kobou, Tama, Crocus and Peacock.
The film was not screened in advance for critics in its initial release, and subsequently fared weakly among them. Janet Maslin of The New York Times said in her short review, "[It] isn't a movie; it's a marketing tool." She was referring to animated fare which, at the time, had just begun the practice of cashing in on pre-sold toy lines. Michael Blowen of The Boston Globe said, "[It] is so incompetently crafted that it makes the Saturday-morning cartoons seem like Disney classics." As for Stuart Fisher, a contributor for Jerry Beck's Animated Movie Guide: "Sorry, kids, the star stealer was here", referring to the zero stars given to it in the book. The Family Guide to Movies on Video called it "Not strong on imagination or substance[,] but lots of color and action designed to sell dolls to the toddler set." Despite its poor reception by critics on review aggregating website Rotten Tomatoes, where it currently holds a rare 0% rating, the audience response was much more positive, holding an 80% rating.
Opening at seventh place with US$1.8 million, and running for just five weeks at a 1,090-venue maximum, Star Stealer grossed US$4,889,971 at the North American box-office, months before a 13-episode syndicated series appeared on DIC's Kideo TV block. A tie-in comic book to the film was issued by DC Comics.
The film was first released on VHS home video in the United States and Canada in 1986. In November 2004, Warner Home Video reissued the VHS cassette and also released the movie on DVD in Region 1 territories with a remastered "open matte" 1.33:1 transfer. Bonus features on the DVD included a sing-along version of the opening song, "Brand New Day", and a "Find the Missing Color Belt" game, as extras.