The title refers to the Brazilian city of Rio de Janeiro where the film is set.
This film starts with Stitch, Angel, Jumbo, Pleakley, David, Reuben, Leroy, Victoria, Sparky and more.
It tells the story of Blu (Stitch), a male blue experiment who was taken to Rio de Janeiro to mate with a female pink female experiment, Jewel (Angel).
He eventually falls in love with her and together, they have to escape from being smuggled by Nigel (Leroy), a evil twin of Blu.
The theme song, "Telling the World" was sung by Taio Cruz.
In Brazil, a various exotic experiment are smuggled out of the country. In Hawaii, a crate with a male blue experiment hatchling falls out of a truck and is found by a little girl named Lilo Gunderson (Lilo), who names him Blu.
Fifteen years later, Lilo owns a bookstore. Blu, highly domesticated and unable to fly, is ridiculed frequently by the 2 experiment that come by the outside of Linda's bookstore.
One day, a ornithologist name Túlio Monteiro (Reuben) invites Blu and Linda to Rio de Janeiro on the condition that Blu (Stitch), who's the last male of his species, mates with a female experiment.
Then, Linda accepts and they fly to Rio where Blu meets a big alien named Pedro (Jumbo) and his another alien friend named Nico (Pleakley).
At Túlio's aviary, Blu falls in love with Jewel (Angel), a confident and independent pink experiment longing to flee into the wilderness.
They were captured by Fernando (Sparky), an impoverished orphan experiment and a evil twin who look like Stitch named Nigel (Leroy), both of who work for a group of smugglers led by Marcel.
While Fernando has second thoughts about his actions, Nigel tells the experiment that he vowed to smuggle experiment in revenge after his role on a television program had been replaced by one.
However, because of Blu's familiarity with cages, they're able to flee into a jungle and they somehow get along.
The next day, Fernando meets Linda and Túlio and tells them that Marcel forced him to capture experiment before cooperating with the two to find Blu.
Meanwhile, Blu and Jewel meet a man named Rafael (David,) who offers to take them to his friend name Luiz (Squawk) to remove their leg chain.
He tries to teach Blu how to fly before they meet up with Pedro and Nico. Then, Nigel hires a horde of thieving monkey to capture Blu and Jewel.
Then, Pedro and Nico take Blu and Jewel to a bird's Rio-style party where they perform a duet, but encounter the monkey right before they were about to kiss.
Their bird friends fight them off while Blu's group escapes. Fernando takes Linda and Túlio to the smugglers hideout where they discover that the experiment have already been moved out.
Marcel, wanting to leave the country as soon as possible to secure a black market deal regarding Blu and Jewel, explains that he'll use the Rio Carnival parade to smuggle the experiment to the airport as all the other streets have been blocked off for the festivities.
Meanwhile, Blu and the others meet Luiz who releases the chain holding Blu and Jewel.
Blu, thinking that his inability to fly will only be a burden to Jewel, argues with Jewel before going their separate ways.
Then, Pedro and Nico witness Nigel capturing Jewel. When Blu and Rafael learn from Pedro and Nico that Nigel captured Jewel, they rush to the carnival to rescue her.
Meanwhile, Linda and Túlio have spotted the smuggler's parade float and organize a rescue attempt for the experiments include Blu and Jewel.
As Linda and Túlio pose as dancers in blue macaw costumes, Nigel captures Blu and the group.
Linda and Túlio fail to stop the smugglers on time and Marcel's group takes off in a Short SC.7 Skyvan.
On board, Blu destroys his cage using his fire hydrant and releases Jewel. Then, they release the captive experiments but, Nigel injures Jewel.
Then, Blu sends Nigel flying into the plane engine using the now active fire extinguisher and the smugglers flee the plane.
Unable to fly, Jewel falls out of the plane's open cargo hatch towards the ocean.
Jumping out of the plane to rescue her, Blu finally discovers that he was able to fly after sharing a brief kiss with Jewel.
Blu carries her back to Linda and Túlio for help. Later, Linda and Túlio adopt Fernando, heal Jewe, and organize a sanctuary to protect the jungle from smugglers.
Blu and Jewel raise three baby kids together and celebrate with their friends while Nigel was ridiculed for his loss of furs and the smugglers are sent to jail.