Spreading about 400 km. (250 miles) in parallel to the Cantabric Sea’s Spanish shore (North to Spain, West to France), the Cantabrian Mountains, located North to Spain between Galicia, Principality of Asturias, Castilla-León and Cantabria are a natural top wall full of animal and vegetable life that live in an extreme conditions along of any year. Making a review along the four seasons, the documentary examines the situation and the relation between 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 and the day-by-day of insects like ants, showing too the difficult of a landscape where danger is everywhere, including in the smallest size. A fascinating travel for revealing the wonders of nature.