Back in school, Alvin, Simon and Theodore must save the school's music programme by winning the battle of the bands. For this, they must beat Brittany, Eleanor and Jeanette, also called The Chipettes.
Leonhard and a group of mushers travel miles to deliver anti-toxin to individuals tormented by an epidemic. However, when his little girl gets the infection, he becomes more associated with the cause.
While holidaying with their families, six children discover that their vacation home is riddled with aliens who intend to conquer Earth using a mind-control weapon.
A spaceship which is shaped like a human and made up of many miniature humanoid aliens lands on Earth. The aliens get in trouble when their spaceship's captain is attracted to a woman, Gina.
Jason Shepherd writes a story that falls into the hands of a Hollywood producer, Marty Wolf. When Marty turns it into a blockbuster movie and takes the credit, Jason vows to make him confess.
The Chipmunks and Chipettes are on a cruise ship when their pranks go overboard. They end up on a deserted, tropical island and soon discover that they are not really alone.
When Cam Harrison, a reporter, hears from his niece about the existence of a mermaid, he is sceptical. He decides to get closer to the creature and see for himself.
Former CIA spy Bob Ho takes on his toughest assignment to date: looking after his girlfriend's three kids, who haven't exactly warmed to their mom's beau.