Spreading about 400 km in parallel to the Cantabric Sea, the Cantabrian Mountains, located North to Spain are a natural top wall full of animal and vegetable life that live in an extreme conditions across any year. Making a review along the four seasons, the documentary examines the situation and the relation of the different species, focusing in the brown bear's life in addition with the salmons travel along of thousand kilometers to return home to spawn, showing too the difficult of a landscape where danger is everywhere, including in the smallest size. A fascinating travel for revealing the wonder of nature.