In this first show of the series Jonny struggles with heights and confined spaces so the hidden world on the fringes of Dartmoor that Bear has selected offers both 50 metre sheer drops and damp cramp caves. Even before their descent into a dank and unwelcoming world Jonny is telling candid tales of how driven and obsessed he was as a child, how a missed kick brought weeks of mental torment and acute fear of failure to a ten-year old Jonny. Climbing hand over hand, an old commando assault technique, Jonny is soon fighting his way up a 40 meter slimy chimney in the rock face but it's the conversation with Bear at the top that reveals the true obsessive nature of Jonny Wilkinson, and how he has learned to harness a force that would drive him to become one of the world's best rugby players but which would ultimately take him to the brink of a mental

Olympic Boxing gold medallist and Strictly star Nicola Adams begins her adventure with Bear Grylls in a quarry in the heart of Dartmoor National Park. Her first challenge is to abseil down a 150-foot sheer cliff. Later, she needs to quickly master a technique where you use upper body strength to pull yourself up a rope.