The Appalachians form a vast mountain chain, stretching along the Eastern side of the USA, from Georgia in the south to Maine in the north. Along much of their length they are clothed in rich but little known woodland, secret worlds of rivers and waterfalls, caves and forest glades inhabited by bears and deer, raccoons and possums as well as dozens of other, lesser known creatures, from hellbenders to social cockroaches. These are the most diverse temperate forests on Earth. In Spring the ground is covered with a spectacular display of wild flowers and in the Fall the hillsides are transformed into a riot of golds and reds, whilst in winter waterfalls freeze into bizarre ice sculptures.

Human history here is just as rich as the natural history. Long before Columbus landed in North America, Cherokee Indians moved into these forests and learnt how to live here. Later, European settlers and then Americans moved here, forming their own unique and colourful culture. Over the course of a year, the film looks at the natural history of these extraordinary forests through the eyes of some of the people living here; those that have an intimate bond to these hills and valleys, each providing a unique perspective on the hidden worlds of Appalachia.