A struggling songwriter named Dave Seville finds success when he comes across a trio of singing chipmunks: mischievous leader Alvin, brainy Simon, and chubby, impressionable Theodore.

Three chipmunk brothers, Alvin, Simon, and Theodore are adopted by human, Dave.

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.

Playing around while aboard a cruise ship, the Chipmunks and Chipettes accidentally go overboard and end up marooned in a tropical paradise. They discover their new turf is not as deserted as it seems.