While the use the Chipmunks " - Concert in Paris, France, Dave (Jason Lee) is bad, after a falling Billboard sends it flies over the stage into electrical devices injured. After the accident Dave is admitted in the hospital. Even if it survives, it must remain to recover. It tells Alvin, Simon and Theodore that, while he away has it its aunt Jackie asked, after the Chipmunks searches, and it has also regulations for it to the school to go. They go up to the airport, where the Chipmunks to meetings with Jackie, which " their grandchildren, Tobin; Toby" Sevilla (Zachary Levi leads). After Jackie stairs and a luggage trolley fall fall into it, it are skillful also into a hospital, so that Toby responsible. In the meantime Ian (David CROSS) lives today into the cellar of the JETT record. A Fedex truck comes around the corner, and a package fails. Three singing strip crescents female called Chipettes result from the packing and place themselves to Ian. Brittany (Christina Applegate) means that since Ian made the Chipmunks stars, it want around stars to be, also. In order to prove its talent, it " sing PUT Your record On" , and Ian rents it. The tension between Alvin and Simon builds as Alvin drives itself with jocks the school, but that, that most strongly affected is Theodore, which believes, loses its brothers, because they fight the whole time. The Chipmunks fulfill the Chipettes and win crushed on their colleagues, are however soon forced, a rivalry after the discovery that they are with Ian, to have. The Chipmunks and the Chipettes against each other in a Battle OF the of volume. In the midday, Alvin meets with Brittany, divides easily romantic moments with it, until he warns her before it, over what has Ian, him and its brothers, and does not believe Brittany it. On the concert, the Chipettes sings " Single Ladies (PUT A ring on It) ". Ian of video tape recordings of the Chipettes achievement and booked it on YouTube, together with its telephone number. The Chipettes the competition to win and Ian becomes richly and famous again after Simon and Theodore purges the competition, because Alvin did not emerge. Alvin shows up later only, in order to see that everyone went. If Alvin returns home, Simon and Theodore maintain, sleep them and ignore it. The embarrassment is to be met too much for Theodore, with it runs away into the zoo. If Toby and the boys retain him and him before an eagle to find, bring it the best from all four of them and the Chipmunks of everything forgives each other and go back too " One for all, and three for one