Plot

Barbie and her athletic best friends slip into their smart outfits when a secret intelligence agency wants to use their special skills to stop a series of gem robberies. Will the Spy Squad succeed in this difficult cat-and-mouse game?

Who would have thought that the athletic and hard-working gymnasts, Barbie, Teresa, and Renee could be thrill-seeking undercover agents? Before long, the girls will find themselves in a fast-paced adventure, when a secret intelligence agency wants to use the inseparable team's special skills to stop a series of precious gem robberies, and to unearth the elusive thief. Now, with a new set of high-tech gadgets and a pair of unexpected companions, Barbie and her sisters-in-arms must work fast in this difficult cat-and-mouse game to prove their worth. Who can stop the mighty Spy Squad?—Nick Riganas

The film opens with a young woman in a rainbow wig, cat mask, and cat ear headband infiltrating a museum, dodging the lasers to the burglar alarm, and stealing a rainbow-colored gem from a display case. She shows amazing gymnastic and athletic skill, and is armed with several technological devices to help her, including one that melts glass into vapor. As she escapes, she cockily smirks and sets off the burglar alarm on purpose, before disappearing into the night.

The next day, Barbie, Renee, and Teresa are training for the Gold Cup tournament with a group floor routine. Chelsea and Mila, training for a junior competition, cheer their big sisters on, as does Renee's elderly and eccentric aunt Zoe, who hasn't missed a meet in years. After warm-ups, the emcee announces the tryouts to be allowed to enter the competition have begun. Several gymnasts go, including a taller and older girl named Patricia who dominates the competition on the high bar. Barbie and the others realize that with her score of 9.9, they'll have to do something pretty special to be allowed in to the competition. They pull off their best routine up until the finish, but the pyramid formation they attempt at the end is not a success, as Barbie manages to psych herself out by overthinking matters and doesn't complete her part of the trick successfully. They get into the competition, but only by the skin of their teeth.

As the three leave the gymnasium, Barbie is irritated that she got into her head so much and messed things up. To celebrate their getting into the competition, Aunt Zoe texts them that she's arranged a picnic at the top of Mt. Lee, near the Hollywood Sign. They head up there with their picnic gear, but when they arrive discover a secret entrance in the "Y" of the sign, which leads them through a series of electronic doors and scanners to the headquarters of what is clearly a secret agency. The people there seem to have every kind of cool gadget on the planet, up to and including an automatic pizza maker, and no one seems surprised or even very interested at the presence of the girls. Aunt Zoe meets them, and explains her 'crazy cat lady' persona is really only a facade, and that she is actually the director of this chapter of the agency. She is also from England by birth and when talking in her normal voice has a strong English accent - this rather freaks out Renee, who had no idea up until this point. She reveals, much to the group's astonishment, that she has sent for them because of their skills as a gymnastics team, to combat the athletic cat burglar who has been stealing gems recently.

Barbie and the Girls sit down with Zoe and her assistant, Agent Dunbar, and review the case. SEcurity footage of the cat burglar setting off the alarm as she leaves the scenes of her crimes shows her athletic skill and cockiness. She is targeting only a certain type of crystal gems, the complete set of which are scattered across collections of museums and rich people all around California. This set of gems was deliberately scattered and sold because they were initially part of an electromagnetic pulse weapon that the agency was developing. The weapon was proved to be far too powerful to control and could possibly cause irrevocable damage and blackouts to the infrastructure of every country in the world, among other things. The weapon was dismantled and the plans were supposed to be destroyed, but these plans were lost or stolen before this could come to be. The agency fears that someone is attempting to rebuild the weapon and has hired this cat burglar to steal the gems for them. They want Barbie and her friends to use their skills to quietly follow the cat burglar, retrieving any crystals if they can, and find out who she is working for.

Initially, Teresa is very hesitant about accepting the mission and entering training, but the other two are so enamored of the idea that they immediately follow Agent Dunbar and Aunt Zoe's robotic assistant cat Violet as they show them around the agency and where they will be training. According to intelligence, they have only 24 hours to train before the thief tries for the next jewel, so he gets them suited up an takes them to meet Lazlo, the young genius in charge of most of their new devices, and Percy, Violet's dog-like counterpart in charge of accompanying the girls on their missions. Lazlo immediately falls for Teresa, and she for him, due to a shared love of robotics and programming.

Among other things, they discover their suits can make them temporarily partially or fully invisible, that they can all make their faces look like Lazlo's, and other helpful things like glitter bombs, grappling hook backpacks, and a device Barbie particularly enjoys called a GLISS, which acts as a vaulting pole and a boomerang rolled into one. After training hard with Agent Dunbar, they set out on their new motorcycles from the agency to the place where one of the remaining three jewels is being kept, at the top of a high building. When the girls arrive, carefully making their way through a laser field that protects the gem, they discover that the cat burglar has already stolen the gem, and is waiting for them. She taunts them as they furiously chase her, using her superior skill to evade them. As the girls follow her with their grappling hooks, rappelling down the sides of the building, Teresa suffers from a spell of vertigo and cannot continue, after her hook shifts. Renee stay behind to help her, and Barbie continues alone. However, the thief mocks her and successfully gets into her head, waiting for her to catch up and telling her she isn't being a good friend to the rest of her team. Barbie finally abandons the chase and returns to help Renee with Teresa, just as the latter's hook comes undone. Percy and Barbie save them from falling to their deaths, but in the process the thief gets away, using a motorcycle not unlike the one the girls were given by Lazlo to escape.

The next day, the girls are still upset about their failure, as is Agent Dunbar, who is contemptuous of their youth and inexperience, but Aunt Zoe encourages them by saying there was nothing they could have done, and that they simply have to try again. As Lazlo shows off more gadgetry and outfits for them, Barbie goes off alone to train some more. Aunt Zoe gives her some pointers on how to keep her focus and confidence and not psych herself out. The next gem is being held at a mansion where a gala is scheduled to occur. With Percy's help, and some costumes from Lazlo, they infiltrate the gala as chefs while Percy communicates to them via their earbuds from outside to let them know of any danger. Once inside, the real chef presses them into service helping him, causing a delay until the girls cause a huge mess in the kitchen that allows them to escape. They then use their computerized costumes to change appearance to look like patrons of the Gala, and get in position to guard the gem, just as a power surge causes a blackout. Percy tells them he sensed someone up on the far end of the building, but just as they get there someone cuts his communication. The girls realize it was a trick to lure them from their spot, and sure enough encounter the thief, who again already has the jewel and has waited for them to catch up, enjoying taunting them as she makes her way across some gigantic lighting sculptures that span from balcony to balcony. There is a large gap between two of them, and the thief does a triple Arabian flip, something thought impossible, to get across the gap. She mocks Barbie and asks why they bother to try to keep up with her, and as Barbie attempts to make the jump and nearly falls to the floor, the thief again escapes into the night.

With only one jewel left, Aunt Zoe's superiors tell her to scrap the gymnast program and send Barbie and the other two home. The stakes are now too high and it isn't as important to keep up with and follow the thief anymore as it is to have someone guarding the jewels. Percy is devastated to see them go, as is Lazlo and Aunt Zoe herself. They return, dejected, to their gymnastics training. However, Lazlo secretly smuggles their motorcycles and other gear to them, saying they can have the fun of messing with them for at least one more day before he takes them back.

At training, Barbie watches Chelsea attempting a standing flip but failing, and gives her the same advice on focus Aunt Zoe gave her. It works, and Chelsea completes the trick successfully. Barbie then overhears the older gymnast Patricia use the phrase "I don't know why you bother to keep up with me", and recognizes her voice, though of course without her wig and cat costume she bears no resemblance to the thief. When she does a triple Arabian flip to dismount the high bar, the girls' suspicions are confirmed. Patricia, when confronted, indicates she deliberately let them know it was her, because she knows they can't do a thing about it, and leaves. Now both infuriated and intrigued, the girls decide to suit up against orders and follow Patricia when she steals the last gem. She gives them the slip, but this time Barbie was able to get close enough to put a tracking device on her motorcycle, undetected. The girls take their time and follow the signal, and are led back to the Hollywood sign and the agency. Entering via stealth mode with Percy's help, they follow Patricia by sneaking through the air vents, and watch as she gives the last crystal to Agent Dunbar. Teresa tries to get hold of Lazlo and Renee tries to get hold of Aunt Zoe, but no one answers. However, Lazlo belatedly returns the missed call just as they get close enough to hear Patricia and Dunbar's conversation, and the ringing wristwatch phone alerts Dunbar to their presence. Teresa barely has time to tell Lazlo what's going on before Dunbar uses several reprogrammed training bots to capture them.

Dunbar reveals that when the project for the Electromagnetic Pulse weapon was canceled, his promotion was also canceled with it, leaving Aunt Zoe to be the director of their division. Having seen the destruction it's capable of, and being rather power hungry, he intends to first disable the agency's massive super computers as revenge, and then use the weapon to rise to power unchallenged, possibly even becoming a global dictator if the weapon is as powerful as predicted. Patricia, who thought this was all a stunt and did not realize what she was stealing the gems for (she just wanted to earn some cash on the side and the stunt appealed to her competitive nature), immediately breaks ties with Dunbar, not liking where this is going. He tells her she has to pick a side but she says she is her own side, and easily uses her skills to evade him and escape. He and a group of the training bots set off to find the main supercomputer of the agency, leaving the rest to hold the girls captive. Lazlo appears, and Barbie uses her GLISS to break free while he and the other two fight and subdue the training bots to get them back to their original programming, planning to follow her.

Barbie pursues Dunbar through the agency, which is deserted for the night. He uses his own training and skills to fight her off, with the aid of his robots. Patricia, who has not yet left, reluctantly joins in to help Barbie to try to stop him, not wanting to be part of the larger crime and possible war. She admits also that seeing Barbie and the others work as a team has got her to rethink her "always work Solo" mantra. Lazlo, Percy, Violet, and the other two girls arrive with the reprogrammed training bots, but Dunbar sets off the weapon just as Aunt Zoe arrives with two of her own bots, to denounce his treason and apprehend him. He is arrested and flown away by the bots, but laughs that they are too late to stop his revenge against the agency. Sure enough, the weapon has powered up and proceeds to emit powerful energy pulses, disabling Violet, Percy, and all the technology in the area except Barbie's Gliss. The weapon is too strong to be broken, though several try, and at Patricia's suggestion Barbie uses the Gliss to pry out one of the gems. This causes the machine to short circuit and fail before any permanent damage is done.

The girls are reinstated as secret agents, though allowed to continue their gymnastics as well. With Barbie, Renee, and Teresa's Testimony for what they overheard, as well as for her redeeming actions during the showdown with Dunbar, Patricia is acquitted on most of the charges against her and given probation - however, this means she cannot compete in the Gold Cup competition . She cheers Barbie and the girls on with Chelsea, Mali and Aunt Zoe from the stands as they perform their group tumbling routine, this time completing all the tricks successfully and earning first place in the competition. Afterwards, they are asked if they would like to participate in another mission and eagerly suit up to do so.