Due to a science experiment, the dogs Max, Rocky, and Gizmo are given the ability to read and discern human words. Using this new ability, the three friends follow beacons left by another friend's owner to the south, hoping to find the lost humans who have vanished from the world.
Dogs Max, Rocky, and Gizmo journey deep into the desert, intent on reaching the silver wall that separates them from their families. They are helped along the way by a ragtag group of friendly animals, and encounter wolf pack leader Dolph one more time for a final showdown.
Canine heroes Max, Rocky, and Gizmo meet a friendly new community of dogs--and these new dogs have seen humans, who Max, Rocky, and Gizmo thought had disappeared without a trace.
When all humans in his world disappear, Max, a yellow Labrador Retriever, searches for Madame Curie but as he and friends Rocky and Gizmo search, they face wolves, subway rats, and the Corporation, a supposed "perfect" society for dogs.
