In the second of four special programmes, Kevin McCloud looks at the challenges of self-building in the UK's most remote places, where beautiful landscapes often meet savage weather. Drawing on footage from 15 years of the programme, as well as new visits to extraordinary and incredible homes, Kevin reveals which designs work best, and why. Along the way, he interviews pioneers at the forefront of architecture in the wilderness and sees the astonishing lengths people go to live on the edges of society.