The brown bear, wolf and chamois, living in the Spanish mountains, must protect themselves from the dangers of extreme cold, avalanches and blizzards. In this hostile world lives the Bone Breaker, a bird with a 3m wing span that is half eagle and half a vulture. This bird uses a strange technique to eat: It collects large bones and flings them down from 150 m onto the rocks below until they break into bits. The it eats the the bones and the bone marrow.