A beagle named Olive saves Christmas after one of Santa's reindeer breaks his leg. Four kids - Ana, Jack, Kate and Zander - hear on the radio that Christmas may be cancelled if Santa can't balance his sleigh. They remember their neighbor has a dog named Olive and decide to take her to the North Pole to replace the injured reindeer. Along the way, they are pursued by a grumpy mailman who doesn't want to have to deliver more letters if Christmas isn't cancelled. With Olive's help biting the mailman, the kids make it to Santa's workshop and explain the situation. Santa agrees to let Olive be the replacement reindeer and they deliver all the presents on Christmas Eve