Ally is a Golden Retriever who has only had other dogs as companions. But when Dave adopts her, Ally will now have to try and live with the Chipmunks and the Chipettes as family members. As Ally tries adapting to her new life, can she try and prove herself, or will her canine ways make life all the more difficult?

Life is full of surprises. When the Sevilles discover Charlie, a Straw-Colored Fruit bat in the Chipmunks and Chipettes closet, they don't know what to do. As they get to know Charlie, they all soon discover that Charlie is actually from somewhere else. Will Charlie be able to stay with the Chipmunks and Chipettes, or will he have to say goodbye and go back to his old home?

Simon and Theodore have always been brothers and best friends. But when Simon saves Theodore from getting hit by a car, Simon gets hit instead and gets Amnesia. What's worse, Simon can't remember Theodore! Now, Theodore must help Simon to get familiar with him again, and re-build their bond of friendship. Will Simon's memory ever come back, or will the old Simon be lost for good?

When Alvin, Simon, and Theodore get assigned to come up with a group costume for Friday's Costume Contest, they have a hard time agreeing with what costume to wear. Then one night, Dave's gone and the power goes out due to a wind storm! The Chipmunks get scared. and thinks there's ghosts! What will they find? Will this spooky night make them work together? Read and find out.