Bear begins with a trek around Snowdonia, a landscape shaped by volcanic eruptions and continental fractures. He starts his adventure in a fast boat crossing Cardigan Bay, which at 50-miles wide is the largest bay in Wales. He also explores Snowdonia, learns more about Britain's smallest bat, and searches for an eco-system hidden in the depths of the North Wales

The adventurer continues to explore the UK's natural history, abseiling at Malham Cove in the Yorkshire Dales and getting into danger in a flooding cave. Malham has long attracted tourists and geologists alike to wonder at its beauty and history, as well as walkers attracted to the limestone formation and its surrounding pathways, and Bear reveals a tropical past to one of North Yorkshire's finest features.

He's trekked around Snowdonia in North Wales and explored the Yorkshire Dales - now Bear Grylls goes north of the border to the Scottish Highlands on an adventure that takes him from the deepest point in Britain to its highest mountain, Ben Nevis. Along the way he goes in search of freshwater pearl mussels, one of the most endangered species in the world, heads for the hills to discover how the country's magnificent highlands were formed and hears about a plan to save an ancient forest under threat because the native Scots pine has been over-run by a non-native species. He also discovers how reindeer are making a comeback and heads up the formidable Aonach Mor, a mountain more than 4,000ft tall with treacherous steep ice walls.