After a concert mishap lands Dave in the hospital, Alvin, Simon, and Theodore end up in the care of his twenty-something cousin, Toby. They put aside their stardom to return to school to win an annual "Battle of the Bands" competition to save the music program, but they meet their match with the Chipettes: Brittany, Jeanette, and Eleanor, who work for their ex-manager, Ian Hawke. The Chipmunks and the Chipettes square off; romantic sparks and crazy mishaps ensue.