Pop sensations Alvin (Justin Long), Simon (Matthew Gray Gubler) and Theodore (Jesse McCartney) end up in the care of Dave Seville (Jason Lee)'s twenty-something cousin Toby (Zachary Levi). The boys must put aside music super stardom to return to school, and are tasked with saving the school's music program by winning the $25,000 prize in a battle of the bands. But the Chipmunks unexpectedly meet their match in three singing chipmunks known as The Chipettes—Brittany (Christina Applegate), Jeanette (Anna Faris) and Eleanor (Amy Poehler). Romantic and musical sparks are ignited when the Chipmunks and Chipettes square off.