On 1500 metres above sea level, on the slope of the mountain Hallingskarvet, stands "Tvergastein', the cabin of Norwegian philosopher Arne Naess. In his life he has spent nearly 12 years in this hut, where he wrote several books and essays on philosophy and ecology. In this film, Naess tells about the concept of 'deep ecology', which was first introduced by him in 1973. One of the basic tenets of deep ecology is that nature has a value in itself, apart from its possible use value to humans. Next to being a famous mountaineer, Naess has been a longtime activist in the environmental movement. He gives an inspiring account of his participation in blockades to prevent the Alta river in northern Norway (the area of the Sami, an indigenous people) from being dammed.