Long ago a prophecy decrees that the already-dimming stars will stop their cosmic dance altogether and go dark, until "The One" is able to help restore order to the Galaxy. The wise but rigid King Constantine, who loves dignity, order, and precision, is firmly convinced he must be "The One" and cooks up a plan with the help of his right-hand robot Artemis.On the far off reserve planet of Para-Den, Barbie has the ability to move and communicate with animals and objects telekinetically, and uses it to help care for the many birds and animals. She and her father reveal her mother had the same gift, and they moved to Para-Den when her mother was ill and dying because her mother's dream had always been to live on an animal Sanctuary. Barbie attempts to save a young bird-like creature who is falling behind the flock, but is knocked off her hover-board by the baby's enraged parents and has to use her powers to retrieve it. Her father commends her kindness and good intentions but shows her that the parents had not abandoned the baby and were trying to encourage it to learn on its own. He warns her that she has a bit of a habit of being impulsive, though he admires her spirit and feels it is better she do what she thinks is right. She and her father feed the animals, using her powers. A strange hybrid creature of a hamster, butterfly, cat, dog, and other species follows them around and behaves as a pet, and Barbie's father explains that he is a young Pupcorn, and like all his kind, when he's old enough and ready, he'll "pop" and morph into a more traditional animal, but there's no telling what he really is on the inside right now.King Constantine's message bot arrives and summons Barbie, as she is the current Galactic regional champion at hover-boarding. Barbie is honored but scared to accept, as she's barely traveled to any other planets and knows little of outside life, but her father reminds her of the importance of the mission. As they look at a locket with a hologram of Barbie's late mother, he gives her an encouraging speech he once heard from his wife, about trusting one's instincts but also using them wisely. He also encourages her to use the leadership skills he knows she has. Barbie decides, after singing a song about confidence that her mother taught her, to accept the mission.Constantine holds a ball to greet his assembled team, and Barbie meets the others - champion pilot but always hungry and socially awkward Prince Leo, sarcastic all-time hover-board gold medalist and speedster Sal-Lee, and the kindhearted and telepathically connected alien twins Kareena and Sheena, who also have gravity powers (one can raise things, the other can lower things). At the ball, Leo is forced by Sal-Lee to try to dance and is humiliated. Barbie teaches him to feel his own rhythm and dance to a more modern beat, and the rest of the ballroom catches on and the DJ stops the classical music and starts a rave. However, Constantine immediately chides Barbie and puts a stop to it, for he sees it as disorderly. Later, during a late-night practice with their hover-boards, Barbie and Sal-Lee , the head of the team, begin to bond over their shared loneliness and fear of losing the stars. Sal-Lee admits her life as a champion hover-boarder means she has never had a permanent home and that stars were, until they started going out, the only constant in her life.The next day, Constantine outlines his plan to infiltrate the center of the galaxy using the skills of his assembled team, to use a device of his invention to force the avatars of the stars into an orderly pattern again. Barbie and Leo are giggling and talking through his demonstration, so he pits them against each other in a sparring contest, hoping to teach them a lesson. However, they both turn out to be unexpectedly good at Parkour. Next, he sets up a hover-board course in which Sal-Lee and Barbie are to compete, each with one of the twins riding along with them, to simulate how they will infiltrate the gravity fields and also to determine who is the better hover-boarder. However, Barbie soon discovers that when the four of them work together instead of competing they do much better. She uses her powers for the first time in front of Constantine, to save Sal-Lee from crashing into an obstacle. This both impresses and disturbs Constantine, as it is against his routine and plan.Sal-Lee reluctantly thanks Barbie for saving her, not liking to give up her tough front. Just then, Pupcorn grows up to reveal his adult form is a giant cat. He is excited, until he realizes he can no longer fly. Some sprites who work as palace servants stay up late with Barbie to create a wing-suit with propellers for him so he can fly with her, but when the cat tests it out he flies straight into Artemis' arms. Constantine, who is with Artemis, is upset that Barbie is up past curfew. He lectures her on how this is not a time, however kind her actions are, to go against any orders as the situation is critical and all must show discipline. He warns her not to make him have to have this discussion again.The next morning, Constantine orders the team to fly to a remote planet to capture a giant, tame creature called a Starlean, known to shyly fly between planets and be elusive and hard to find. Tired of being pestered with questions and objections, he refuses to explain what this has to do with anything, much to the team's chagrin. With Leo's skill as a pilot and Barbie's skills at rhythm and music, they succeed in luring a truly gigantic Starlean out and getting it to dance with them. However, when they spring the trap Constantine invented, the creature feels betrayed and starts to wail miserably. Barbie senses the bound creature's fear and distress with her powers - fearing Constantine wants to put the Starlean in his extensive zoo and able to tell with her powers it would not survive in captivity, she immediately uses her telekinesis to free it, with the support of her friends. Constantine, furious at her assumption he would have killed the creature, immediately fires her - only Starleans can find the center of the galaxy, where the avatars of the stars all reside, and without one the mission will fail. When the team all object to this, and remind him he didn't tell them so they weren't to know, he angrily tells them they need to learn to follow the king's orders and stop questioning them. Barbie, inspired by something her father said and the song from her mother, desperately attempts to make things right by telekenetically summoning the Starlean back. Surprisingly, it flies across space, willing, now it is not bound, to be of service. She brings it to see the king, though she only apologizes for her wrong assumptions about him, not for her actions freeing the bound Starlean, since it wouldn't have served them if bound. When Constantine is still hesitant to reinstate Barbie, whom he sees as a loose cannon and a risk, the Starlean, mistaking him for an enemy, begins to growl and defend her until Barbie convinces it he is a friend. Constantine recognizes she saved his life and that the mission can't be completed without her, and grudgingly acquiesces to reinstating her. Sal-Lee immediately forfeits her position as team leader to Barbie, with Constantine's reluctant blessing.The next day, Constantine and the team set out with the Starlean's help to find the central planet of the Galaxy. Constantine brings the special device he invented with him. Leo pilots them skillfully to their destination, with the Starlean protecting them from magnetic storms and other dangers until they enter a crevice too small for it to follow. Leo lands the rocket, and Barbie, Sal-Lee, and the twins use their teamwork skills to navigate through a field of dangerous electromagnetic orbs that supposedly guard the way to the doorway that leads to the core, with Constantine following in a hover-chair and Leo hanging on for dear life to Pupcorn as he flies after them. The other side, however, appears to be a dead end, with no doors or exits in sight. Constantine's studies lead him to believe there is a door hidden, so the team begins to look. Belatedly arriving, Leo finds and playfully pushes a button in the floor, opening a trapdoor that sends them all falling to the core of the planet, where the twins again use their gravity skills to save the group. Here, they find the avatars of the stars - millions of tiny orbs, floating but dim and still. Constantine, ignoring Barbie's advice to look around and listen to the stars, uses his device right on schedule, as planned. The apathetic stars, zapped into a forced order, become miserable and immediately all fall to the cave floor and go out, plunging everything into darkness and Constantine into despair. Barbie, hearing one little star orb singing softly, remembers the part of her mother's encouraging speech that said that maybe the stars forgot how to dance because no one ever came to dance with them and they were lonely. She communicates to them through her own powers and song, starting to dance across the planets core. The avatar orbs of the stars join her joyfully, rising and filling the room with light as they dance, and on the outside the true stars burst into light and song, restoring more light and beauty to the Galaxy than ever before.The team returns to a hero's welcome. Constantine, thoroughly humbled, admits to Barbie that while they are both irrevocably different in temperament and will likely never change, this is not necessarily a bad thing. Barbie is named "Princess Starlight" and invited to live as Constantine's ward in the castle, along with her father. When she hesitates, Constantine suggests that he wants her around as much as the team and the palace subjects, as they can learn a lot from one another. Barbie ends the film with another rave, as she, her father, and friends teach Constantine to dance for the first time in his life.