In the modern Kingdom of Windemere, Princess Kara helps her two friends, royal inventors Mikayla and Madison, to test out a new jet pack machine, while also searching for a site for her dream project - the Windemere Community Garden. As she returns to the Palace, just as her parents are arriving home in their limousine, she crash-lands the device in a tree. Her mother and father, King Kristoff and Queen Carina, immediately panic over her and make sure she is okay, even though she is standing and clearly uninjured. They berate her severely for the escapade, and when they hear she wants to do a community garden, they refuse, saying she shouldn't have risked her safety for something like that, and say the best way she can make a difference in the kingdom is to just smile, wave, and be a royal presence at galas and openings right now, much to her disgust.Meanwhile, the King's advisor, Baron Von Ravendale, and his assistant frog Bruce are busily working to create a potion that will grant the drinker super abilities. Ravendale contends that when the Kingdom of Windemere was discovered centuries past, his ancestors were the rightful rulers, but lost the kingdom to Kristoff's ancestors in an unfortunate bet. He maintains also that he could do a better job than the well-meaning but gullible and overprotective Kristoff. Unfortunately, just as he is about to drink the potion, it literally goes down the drain - Bruce was chasing a fly and knocked over the vial, and it went down a storm drain in the cellar floor. Ravendale is furious, having no more ingredients for his potion, and knowing it's going to take a long time to regather the ingredients. Unbeknownst to them, a caterpillar going through the sewers en route to the garden absorbs the potion, and when, some days later, it undergoes metamorphosis, it still has a lot of the potion clinging to its body and wings.Kara complains to her friends, her cousin Corinne, and her little sisters Zooey and Gabby about her parents being increasingly overprotective as she gets older and how her role is no more than a figurehead, making no differences. Her mother won't even let her cut the ribbons at openings for fear of the scissors. Corinne, highly jealous, angrily remarks that Kara needs to just get over it - to Corinne's mind, being royal at all means you have no right to complain about anything. The potion-covered butterfly flies by and Corinne tries to kill it. Kara saves it, and it gives her a kiss, transferring some of the potion to her. She becomes disoriented and faints.The next morning, Kara awakens to frantic barking from her dog Newton. THe palace cat, Parker, is stuck on a fast-cracking branch in the same tree that Kara crash-landed in, earlier. The Baron, as the King and Queen are away, sends Bruce to find the ingredients for his new potion, and takes the time to get used to sitting in the throne, as he feels that once he remakes the potion it will soon be his. Kara rescues Parker but the branch cracks - however, they don't fall, but wind up hovering outside the window, only narrowly avoiding being seen by Ravendale. She manages, after a lot of off-balance flopping, to sort of fly around a bit, before crashing into the tree. SHe immediately goes to talk to Mikayla and Madison, who use their scientific knowledge to help her run a few tests to see what powers she has. It transpires that besides flight, she has super strength and agility, and can fire energy balls from her hands. They go out for a test drive, and after a lengthy flight around the woods and dormant volcano outside Windemere, Kara returns to the palace only to crash into the same tree again. She determines that this tree has to go, and uproots it with little effort at all. However, Mikayla and Madison get her to see that she shouldn't use powers for gain and personal reasons, and she begrudgingly replaces it. She decides she could use her powers and a secret identity to create the community garden, her dream project to bring people together in Windemere across class boundaries. The inventors make her a super-suit that transforms into a dress, and she says they'll meet at the community garden spot she picked, before flying off.In the town, Corinne is shoe-shopping when she has a collision with a young man focused more on his cell phone than where he's going. A construction worker, laughing as he watches, stumbles and falls into a trash chute near him, dropping his coffee on the controls of a crane. The young man finds himself about to be hit by a stack of falling pipes when Kara, seeing what's happening, flies down and rescues him from the pipes. She rescues the construction worker, and gets a lot of applause from the crowd. The young man takes lots of pictures of her. She also saves Corinne from a falling I-beam. People ask who she is, but Kara only identifies herself, per the inventors' suggestion, as "Super Sparkle". The young man, after she leaves, gets an interview with the construction worker she saved, and reveals his name is Wes and that he writes Windemere's leading informational blog. Kara returns to the palace and transforms back in time for a gala, then hurries to her room to find the two inventors have also returned and locked it. She explains to them what happened and they show her that, when she didn't show up at the community Garden site, they came back and reset her room so it is an epicenter for her superhero activities, pinpointing when there is trouble the police or fire department can't handle. As time goes on, Kara saves many people and starts to enjoy all the media attention, even posing for a selfie with Wes at one point after saving a man from a fire that Baron van Ravenhurst accidentally set in a refinery/warehouse while stealing an ingredient for his potion. As she reads about her in the news, Corinne is as jealous of Super Sparkle as she is of Kara, and becomes even more bitter and withdrawn. Meanwhile, Kara decides not to continue with the Community Garden project for the time being, much to her friends' dismay. While she does want to help people, it's becoming apparent she is also enjoying for the first time being recognized as more than just a figurehead and is letting the fame go to her head.As Kara's birthday rolls around, her younger sisters want to invite Super Sparkle to the party, and get Kara's permission to wear superhero costumes. Mikayla and Madison gift her a silver ring that also doubles as a communication device. She goes out into the ballroom to meet with her family and the guests for her birthday, with Mikayla and Madison also wearing super costumes - failed versions of the costume that Kara wears as Super Sparkle, which they kept for such an occasion. Wes is one of the guests, and asks Kara if she thinks Super Sparkle will show up. She remarks it isn't likely, and lets him take a photo of her before going to join her parents. When she hears them boasting of how proud they are that their kingdom has Super Sparkle - things they've never said to her - she becomes angry, and confides in Mikayla and Madison she wishes she could just tell her parents, though she knows as soon as they know they'll put a stop to it, wanting to keep her safe as their eldest heir. They remind her that they started this to help people, NOT for the recognition. Just then the bank is robbed and the one officer in pursuit has lost the criminals. Kara sets off, begging her friends to cover for her until she can get back. She stops the robbers with some difficulties, but in the process loses her silver ring, and the inventors have to make her a new one.When she returns to the palace, a suspicious Corinne happens to see her transform back and realizes the truth. Furious that Kara not only is getting the royal life she wants but also the media attention as Super Sparkle as well, Corinne decides to let the inventors know that she knows Kara's secret. As she expects, they immediately panic and whisper about the butterfly that gave Kara her powers, wondering if Corinne saw that. Corinne, now knowing how Kara became a superhero, is determined herself to be a hero and steal all of Kara's thunder. She hunts for the butterfly and finds it, kissing it and gathering the same powers as Kara.The next day, Baron van Ravenhurst is on a large cliff overlooking a highway, trying to get a rare plant growing on the cliff face as an ingredient for his potion. The ledge's dirt edge erodes and he and Bruce plummet towards the busy highway, only to be rescued by Kara. He doesn't recognize her, with her wig and super suit, but she recognizes him. But before she can ask him what in the world he was doing on the cliff, some of the ledge above erodes further. She flies up to try to stop it, but suddenly Corinne, also in a wig and copycat super suit, appears and introduces herself as "Dark Sparkle", and attempts to stop the rock slide herself. Her inexperience causes her to make it worse, and Kara winds up having to stop and clean up her mess. She is furious there is a copycat out there, and refuses to be comforted by Mikayla and Madison's suggestion that they could someday work as a team.Over the next few weeks, the two compete for media attention, nearly causing some minor disasters in their attempts to "out-help" each other. To make matters worse, Gabby and Zooey, who used to be huge "Super Sparkle" fans, start to imitate Dark Sparkle and Super Sparkle fighting each other, much to Kara's disgust. Things come to a head when Wes sees the silver ring on Super Sparkle's finger and Princess Kara's finger, in two separate pictures he has of them, is the same, and publishes an article blowing her cover. Her parents completely flip sides and instead of praising Super Sparkle's heroics, severely lecture Kara on the danger of her activities and the fact she hid it from them knowing they'd say no. Despite Kara's feeling of betrayal at being told they are not proud of her now that they know her identity, they say that no matter how much she thinks she can take care of herself, they are her parents and responsible she safely grows up to be their heir. Since she is their child under their roof, she must follow their rules, and order that she must retire and let Dark Sparkle take over the protection of Windemere. Kara has no choice but to comply. The Baron overhears this and is glad he now only has one obstacle to deal with instead of two.At dinner, Corinne gleefully teases Kara about what has happened, and gloats that Dark Sparkle can protect everyone without help. Meanwhile, the Baron finally has perfected and drunk his potion, gaining the abilities of flight and shooting energy balls from his hands. He crashes the dinner, and both Corinne and Kara shoot energy balls at him. Kara discovers that Corinne is indeed Dark Sparkle by this action, but at the moment with her parents and younger sisters in danger, there's no time for them to fight each other. Instead they both try to fight the Baron separately, with mixed results. The Baron tries to get Corinne to join his side, as she longs for power, but she, surprisingly enough, refuses point-blank. King Kristoff takes his family to a special panic room in the tower which is completely damage proof.During a lull in the fighting, Corinne mocks Kara and Kara finally has it out with her, questioning her motives for becoming a hero and demanding to know why she butted in, and Corinne tells her she's sick of how she steals the spotlight all the time. Kara angrily demands Corinne "Get your own life because you can't have mine", and Corinne, hurt, abandons her to fight the Baron by herself. Kara makes sure her family get safely to the panic room, but she doesn't go in with them. Her parents realize that she is now the only one who can stop the Baron, and let her go, sealing themselves safely in. Meanwhile, Bruce, who also gained powers by drinking the potion, goes after Mikayla and Madison, still trapped in the castle. Parker and Newton fight him, and Kara arrives to save her friends. Parker and Newton, wanting to help more, run out to where Corinne has the butterfly trapped in a jar.Meanwhile, the Baron blasts the tower again and again but finds that even with his powers he cannot get in and kill the king. He spots the dormant volcano miles outside the town and, after another battle with Kara, heads out and uses his energy balls to break open the seal at the top, allowing it to erupt and the lava to boil out towards the palace. Kara manages to create a new seal, but not before a huge flow of lava heads straight into the palace grounds, weakening the castle foundations and threatening to fell the safe tower. Kara flies back and gets the tower back upright with her super strength, and the lava flows on down the hill towards the city of Windemere below. Kara tries to use energy balls to form a pathway to divert the flow into the river. She isn't fast enough alone, and the lava flow nearly catches up to her. Corinne, who has been watching, joins in and helps her finish the task. She tells Kara that, while she isn't Kara's biggest fan and has her faults, she isn't a total jerk and wouldn't just walk away from saving lives, any more than Kara would, at heart. Kara realizes that she misjudged her, and the two apologize to each other for their petty bickering and agree to try to work together for the time being.The Baron decides to try to take out Kara instead of her family, and after an extended fight he nearly loses, with Brutus' help captures both the girls. His victory is short lived, because Parker and Newton join in, having gained flight and super strength themselves from the butterfly, and free the girls. The four of them work together to corral the Baron and King Kristoff gets his family out of the tower, leaving open the door. The Baron is thrown into it and Gabby and Zooey lock him in, and he finds his powers don't work to get out any more than they did to get in, meaning he's a prisoner there for probably the rest of his life.After all the damage is cleaned up, the King and Queen honor both their royal superheroes, and promise to trust Kara's judgment more in future as long as she is open with them in return. Finally, Kara, with the help of Corinne and her two super pets, her parents, the inventors and her little sisters, gets the community rallied to start the garden, which is immediately a successful project. Wes comes to document the event, but Kara takes his phone from him and puts him to work planting Kale, saying he can have it back when he's done. While not averse to helping, he does playfully ask if she stole his phone because he blew her cover, and she agrees that is the case.