A humpback whale mother and calf embark on an epic journey from tropical coral paradises to storm ravaged polar seas. Newly discovered coral reefs in Indonesia reveal head-butting pygmy seahorses, flashing 'electric' clams and bands of sea kraits, 30-strong, which hunt in packs. Elsewhere plagues of sea urchins fell forests of giant kelp. Huge bull fur seals attack king penguins, who despite their weight disadvantage, put up a spirited defence.

It is high summer in the Polar Regions, and the sun never sets. Vast hordes of summer visitors cram a lifetime of drama into one long, magical day; they must feed, fight and rear their young in this brief window of plenty. Summer is a tough time for the polar bear family, as their ice world melts away and the cubs take their first swimming lesson. Some bears save energy by dozing on icy sun beds, while others go egg-collecting in an Arctic tern colony, braving bombardment by sharp beaks. There are even bigger battles on the tundra; a herd of musk oxen gallop to the rescue as a calf is caught in a life and death struggle with a pair of Arctic wolves. But summer also brings surprises, as a huge colony of 400,000 king penguins cope with an unlikely problem - heat. The adults go surfing, while the woolly-coated chicks take a cooling mud bath. Nearby, a bull fur seal is prepared to fight to the death with a rival. Fur flies as the little pups struggle desperately to keep out of the way of the duelling giants. Further south, a minke whale is hunted amongst the ice floes by a family of killer whales. The dramatic chase lasts over 2 hours and has never been filmed before. The killers harry the minke whale, taking it in turns to wear it down. Eventually it succumbs to the relentless battering. Finally, comical adelie penguins waddle back to their half a million strong colony like clockwork toys. The fluffy chicks need constant feeding and protection as piratical skuas patrol the skies. When an unguarded chick is snatched, a dramatic "dogfight" ensues.

In the captivating second part of “Our Universe”, chapters 4 to 6 are presented together in an unmissable journey through the cosmos and life on Earth. These episodes delve deep into the elements that formed our world, the essential role of water, and the unseen forces that shape our lives. They offer an enthralling exploration of our place in the Universe. Dive in to experience this profound story of existence, from stardust to soulmates.
In the fourth chapter, we uncover how the elements essential to life were forged in the hearts of stars. Following a green sea turtle’s quest across the ocean for these elements, this episode reminds us that life is built from the remnants of ancient stars. The fifth chapter takes us back to the miraculous arrival of water on Earth, exploring how this vital substance transformed a barren landscape into a thriving blue planet. In the final chapter we witness gravity’s grand influence on life, following two king penguins as their journey of attraction and survival unfolds against the cosmic force that binds us all.