Andrew, Judy, and Thudd have landed in the Australian rain forest and are the size of bugs. They navigate through a series of dangerous encounters with rhinoceros beetles, tree kangaroos, a carnivorous plant, and a carpet python as they search for a way to reach the river and find Uncle Al. The adventure is fraught with peril as they face the question of whether they will ever reach Uncle Al or remain shrunken in the Australian wilderness forever.