David Attemborough introduces us to the Antarctic world where temperatures drop to minus 70 degrees and winds of over 160 km an hour scour the ice. Few animals can survive in the worst conditions on earth. The seals, trapped by the ice now covering the sea, struggle with their pups to maintain holes giving them access to food. The marine world under the ice is one of mysterious shapes and beautiful caverns as well as unexpected forms of life. Only the emperor penguin seems able to cope with the cold and dark Antarctic winter and protects a single egg against the storms while the Aurora Australis illuminates the sky. It was to collect an emperor penguin's egg that three men from Scott's expedition set out in midwinter for what has become known as "the worst journey in the world". Man had begun the exploration of Antarctica.