Usagi and friends go to a around a world trip with the chipmunks and the chipettes. But also face a new enemy. (PowerPuff girls z are the guests stars in the movie.)
When David Seville goes off to Europe on a business trip, the Chipmunks, Alvin, Simon and Theodore are left at home with their babysitter, Miss Miller - much to the dismay of Alvin. While the three are playing an arcade game of Around the World in Thirty Days with the Chipettes, Alvin and Brittany argue over which would win an actual race around the world. Diamond smugglers Claudia and Klaus Vorstein overhear the conversation and approach the children, telling them that they will provide them with the means for a real race around the world byhot air balloon, with the winner receiving $100,000.
After tricking Miss Miller, the Chipmunks, Chipettes, Usagi and the team meet at the Vorsteins' mansion, where they are told the rules: each team--the Chipmunks, Usagi and the sailor team being one, and the Chipettes, Rini, Blossom, Bubbles and ButterCup being the other--is given a separate route to follow, along with a chest of dolls, made in their own likenesses, which they are required to drop off to verify that they have visited all checkpoints. Upon dropping off one of their own dolls, they will receive a doll made in the likeness of a member of the opposing team. In reality, the dolls being dropped off are filled with diamonds, and the dolls received are filled with cash, given to them by the buyers. Both teams begin their travels; while the Chipmunks and the sailor team go to Mexico City, the Chipettes, Sailor Mini Moon and the powerpuff girls are caught in a hurricane and Brittany comes very close to becoming eaten by a shark in Bermuda. Unknown to both teams, however, they are being chased by two INTERPOL agents, sent by Inspector Jamal, who has been informed by Claudia and Klaus' butler, Mario, of the Vorstein's operation. The agents silently follow behind as the Chipmunks and Chipettes travel to many exotic locations. Both teams meet up in Athens, where Alvin and Brittany begin bickering, each claiming they can "out-rock and roll" the other, with Dave and the two INTERPOL agents nearly spotting them.
The Chipettes,Rini, Blossom, Bubbles and Buttercup then travel on to Egypt, where they are captured and brought to a young Arabian prince. The prince falls in love with Brittany and, oblivious to the diamond smuggling, agrees to return the valuable dolls to Jamal but declares that he is keeping the girls, and making Brittany his bride. Despite being showered with gifts, including a baby penguin, the Chipettes,Rini,Blossom, Bubbles and ButterCup are desperate to make an escape. Still unaware of the contents of their dolls, they secretly try to retrieve them - only to find them guarded by snakes. Brittany,Jeanette, Blosssom, Bubbles and ButterCup "charm" the snakes by singing "Getting Lucky", then grab the dolls and escape just as Eleanor and Rini arrives carrying a small cooler.
Meanwhile, the Chipmunks, Usagi and the sailor team are camping in a jungle near a native village while taking a shortcut. Theodore senses something is wrong; Simon and Alvin don't believe him. Upon waking up the next morning, they find Theodore missing. While trying to find him, Alvin,Simon and the team are taken captive by some local natives. They soon learn that Theodore is being worshipped as the natives' "Prince of Plenty". Alvin and Simon are quickly forced to wear loincloths and are made into Theodore's personal servants.
Meanwhile, the Chipettes, Rini, Blossom, Bubbles and ButterCup learn that Eleanor's cooler contains not food, but the baby penguin, whom Eleanor feels needs to be returned to its parents in Antarctica. The girls soon decide to head to Antarctica and sing the song "My Mother". However, Claudia is alerted to the girls' actions by her henchmen, and concludes that they must have discovered the diamonds and are trying to escape with them. She orders her henchmen to get the dolls back. As the girls deliver the young penguin to its parents, they are attacked by Claudia's henchmen. The Chipettes,Rini, Blossom, Bubbles and ButterCup wrestle with the men as they attempt to steal the dolls, and a doll tears as the henchman falls from the balloon. Grateful to the Chipettes, Rini, Blossom, Bubbles and ButterCup, the penguins snowball the henchmen into submission as the girls escape. They then notice the torn Chipette doll lying on the floor of the balloon; Jeanette picks it up and diamonds fall out of it. Opening a Chipmunk doll, they find it full of dollar bills, and realize that the whole race was just a set-up to deliver the diamonds. Rini, Blossom, Bubbles and ButterCup realizied that the Chipmunks, Usagi and the sailor scouts are likely in danger as well, they head off to find them.
Alvin,Simon and the sailor team, meanwhile, are forced to search a nearby cave for mushrooms, with Alvin growing increasingly fed-up with the situation. Inside the cave, they find a series of ideograms on the walls, which Simon and Ami are able to translate -thanks to his vast intellect. The ideograms tell of the Prince of Plenty being sacrificed on a full moon, which is that night. Before long, all three Chipmunks and the sailor team are tied to stakes by the natives, hanging precariously above a pit full of crocodiles. In a desperate attempt to delay their own deaths, they sing "Wooly Bully," which pleases the natives and lasts just long enough for the Chipettes, Mini Moon and the PowerPuff Gilrs to rescue them.
Together in the Chipettes' balloon, the kids return to Los Angeles, where they are met at the airport by Claudia and Klaus. After a high energy chase through the baggage claim (as the Chipettes sing Diamond Dolls), the two groups are forced into a car under the false threat of Miss Miller's being kidnapped. Dave is arriving home to the airport at the same time, and hears Alvin's cries for help. Inspector Jamal runs up, identifying himself, and he and Dave begin to make a chase. While it at first appears that Claudia and Klaus will escape, they are accidentally run off the road by Miss Miller as she is heading to the airport to pick Dave up. The diamond smugglers are arrested, and Brittany and Alvin argue over who really won the race, but Dave breaks up the argument and guides them to Miss Miller's car. Dave tells Alvin that he and the Chipmunks and the Chipettes have a lot of explaining to do. Alvin repeatedly protests about being entitled to the promised prize money, causing Dave to yell "ALVIN!" as the film ends. Afterwards Usagi, the sailor team and the PowerPuff Girls go off to a new adventure.