Gregor and the Uncharted Lands

Three years have passed since Gregor and his family moved to Virginia. They've all started a new life away from the Under Lands albeit they still strongly remember their adventures there. All but little boots. What if the uncharted lands spread all over the U.S. And the under landers never knew. What would happen if Gregor find a tunnel into the uncharted lands from the forest surrounding his family's farm. An area populated by a different set of humans with a slightly different life style.