George and Gracie begin their adventure in Dover, Delaware 1776. The kids are surprised to discover that one of them changes into an animal every time they travel, and this time Gracie is a horse. All the twins want to do is return a pair of antique school desks and search for their parents. But instead they find themselves in the middle of the American Revolution and end up helping Caesar Rodney make his famous ride into Philadelphia to vote "yes"...