Spring arrives in the polar regions, and the sun appears after an absence of five months; warmth and life return to these magical ice worlds - the greatest seasonal transformation on our planet is underway. Male Adelie penguins arrive in Antarctica to build their nests - it takes a good property to attract the best mates and the males will stop at nothing to better their rivals! But these early birds face the fiercest storms on the planet. In the Arctic, a polar bear mother is hunting with her cubs. Inland, the frozen rivers start to break up and billions of tons of ice are swept downstream in the greatest of polar spectacles. This melt-water fertilizes the Arctic Ocean, feeding vast shoals of Arctic cod and narwhal. The influx of freshwater accelerates the breakup of the sea-ice - an area of ice the size of Australia will soon vanish from the Arctic. On land, a woolly bear caterpillar emerges from the snow having spent the winter frozen solid. Caterpillars normally become moths within months of hatching, but life is so harsh here that the woolly bear takes 14 years to reach adulthood. Once mature it has only days to find a mate before it dies! Alongside the caterpillars white Arctic wolves race to raise their adorable cubs before the cold returns.

A fifth of the land on our planet is covered by desert. Deserts may appear to be barren and empty, but they are of crucial importance to life. For those that can overcome their challenges they provide a vital refuge. The Grasslands are one of our planet's most productive landscapes. They support the greatest aggregations of large animals on Earth. Cameras follow desert elephants seeking sustenance, bison roaming North American grasslands and caterpillars living the good life underground.

Plants that have developed to thrive in the desert, including cacti that grow in the shade of other trees and collect water in pleated trunks that expand and contract - but can also find themselves a host to other plants, like desert mistletoe. This programme also reveals how tobacco plants being eaten by caterpillars are able to summon the creatures' natural predators, and how tumbleweeds roll across the landscape, only unfurling and growing when they encounter rain.

Predators and prey are in an arms race for survival. Hunters and hunted deploy hidden super- skills in the battle to eat or be eaten. Masterclasses in predatory perfection are vital to passing on skills. So when they're ready to hunt for real, the next generation is fully prepared for the battle between predator and prey.
Life is a mission, survival. Animals have evolved secret weapons and hidden skills to outsmart their enemies. So in those life or death moments, it takes the most extraordinary super powers to prevail.