Dave Seville [Ross Bagdasarian Jr] heads to Europe on a business trip, leaving the Chipmunks—Alvin [Ross Bagdasarian Jr], Simon, and Theodore [Janice Karman]—in Los Angeles with their babysitter. The kids, joined by the Chipettes—Brittany [Janice Karman], Jeanette, and Eleanor, dive into an arcade challenge called Around the World in 30 Days, sparking a lively dispute between Alvin and Brittany over who would win a real-world race around the globe once Brittany wins the game.
Their fun is interrupted when international diamond-smuggling siblings Klaus and Claudia Furschtien hatch a plan to move millions in diamonds and cash by using unsuspecting children as couriers. Claudia spins a deceptive scheme, proposing a real race around the world between the Chipmunks and Chipettes for a tempting prize, and she convinces the kids to participate. To seal the ruse, Alvin records a phone call with Dave and edits it to mislead Miss Miller into thinking Dave wants the Chipmunks to meet him in Europe.
The two teams take off by hot air balloon, each clearly marked with their own route and each carrying twelve dolls that resemble the team members. The idea is simple: exchange the dolls at designated stops to prove they visited the locations, while the cash and diamonds lie concealed inside the dolls the teams exchange. Unbeknownst to them, the dolls contain different valuables, and the adults’ scheme to dodge them is set in motion. The Furschtien household’s butler, Mario, secretly works as an informant for Jamal, who sends two of his men to seize the dolls.
Their first stop is Mexico City, where the kids join in a festive fiesta. In Bermuda, the Chipettes dive to complete an exchange in a sunken ship, and Brittany narrowly escapes a feeding by a great white shark. The journey continues across several countries, with each stop bringing new opportunities and new misadventures as the teams trade dolls and dodge pursuit. In Athens, a musical number on the Acropolis gives both teams a chance to outshine one another, while Dave nearly spots them.
Frustrated by his men’s failures, Jamal enlists a young sheikh whose mercenaries capture the Chipettes in Giza. The sheikh, however, is drawn to Brittany and decides to keep the girl, even presenting her with a baby penguin. The Chipettes sing a charming number to charm the cobras guarding their dolls, escape in their balloon, and detour to Antarctica to return the baby penguin to its family. Claudia, realizing the ruse is unraveling, sends her thugs after the girls. The sisters escape but discover the diamonds and cash inside the dolls, and they realize they have been deceived. Together, they decide to find the boys.
Meanwhile, the Chipmunks venture into a jungle where they are captured by a native tribe and named Theodore their “Prince of Plenty,” while Alvin and Simon are forced into servitude. The natives plan a crocodile pit sacrifice for the trio on a full moon, but the boys stall the execution by performing a spirited rendition of “Wooly Bully” and are eventually rescued by the Chipettes.
Claudia uncovers Mario passing information to Jamal, who is revealed to be an Interpol Inspector. The children finally land at Los Angeles International Airport just as Dave returns home, and a tense pursuit begins. The Furschteins threaten to kidnap Miss Miller, but in a dramatic turn she ends up driving the wrong way on a one-way street and crashes into them, causing their arrest by Jamal. The kids are joyfully reunited with Dave, but Alvin and Brittany end the adventure by quibbling over who won the make-believe race, much to the adults’ exasperation.
