A pioneering team of zoologists and botanists, in search of new creatures and plants, gets rare access to Brazil's highest and most isolated mountain, the Pico da Neblina.
In the third episode, Iain discovers the remarkable impact of just one plant: grass. On the savannah of South Africa he sees how grass unleashed a firestorm to fight its greatest enemy, the forests. He shows how cutting your finger on a blade of grass shows us how it transformed life in the oceans. In Senegal, he meets the cleverest chimps in the world. And, in the ruins of the oldest temple on Earth, he tells the extraordinary story of how grass triggered human civilisation.
Why are vultures bald? Why do some orangutans have big cheeks? And if giraffes have long necks to help them reach the highest leaves, why do they mostly eat low-lying shrubs? Embark on a whirlwind tour around the world as we explore some of nature's most-fascinating evolutionary wonders.
The most extreme and wild parts of New Zealand are in the South Island, which lie towards Antarctica, in the path of the tempestuous 'roaring forties'. This is home to some of the most rapidly rising mountains in the world, the Southern Alps. From hyper-intelligent parrots to sinister snails with teeth and magical constellations of glow-worms, this is the story of New Zealand's wildest places and its most resilient pioneers, all of whom must embrace radical solutions to survive.
Fish dominate the planet's waters through their astonishing variety of shape and behaviour. The beautiful weedy sea dragon looks like a creature from a fairytale, and the male protects their eggs by carrying them on his tail for months. The sarcastic fringehead, meanwhile, appears to turn its head inside out when it fights. Slow-motion cameras show the flying fish gliding through the air like a flock of birds and capture the world's fastest swimmer, the sailfish, plucking sardines from a shoal at 70 mph. And the tiny Hawaiian goby undertakes one of nature's most daunting journeys, climbing a massive waterfall to find safe pools for breeding.
Spy Pup is immersed in wild dog life to explore their maternal love, and Spy Penguin records the turbulent action of the mating season, as a male Adelie penguin falls victim to a pebble thief that ruins his chances of love for the season. Spy Tortoise and Spy Bushbaby keep watch on chimpanzees, while in perhaps the most moving scenes; Spy Monkey becomes the focus of attention for a troop of concerned langurs who believe the motionless camera-creature has died.