Pop sensations Alvin, Simon and Theodore end up in the care of Dave Seville's twenty-something nephew Toby. 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, Eleanor and Jeanette. Romantic and musical sparks are ignited when the Chipmunks and Chipettes square off. The world-famous singing preteen chipmunk trio return to contend with the pressures of school, celebrity, and a rival female music group known as The Chipettes.