Siblings Kate and Teddy try to prove Santa Claus is real, but when they accidentally cause his sleigh to crash, they have to save Christmas.

After arguing with his girlfriend, Ali, Tyler lands in the arms of sexy new girl, Holly. The next morning, he finds that not only does Ali agree ...

Through a series of misunderstandings, Alvin, Simon and Theodore come to believe that Dave is going to propose to his new girlfriend in New York ...