The first episode focuses on coastal habitats. In Shipstern Bluff of Tasmania, a tidal wave from the south burst towards the cliff where the surfer began to surf. On South Africa’s cliffside of Robberg Peninsula, thousands of Cape fur seals are settling onto a small ledge for breeding. A yearling pup began their first time experience of swimming, where the clumsy youngster became nimble and graceful. In recent years, this coast has attracted unprecedented numbers of great white sharks, and the seal colony banded together to fend off against the world’s most notorious predator. The Arctic coast is the scene of the biggest seasonal transformation on earth, and the melting of billions of tonnes of ice brings short-lived opportunities to these coastal waters. During spring, animals arrive en masse, perhaps the strangest of which is the sea angel. This beguiling creature has revealed its devilish side as it preys on a strange winged snail-like invertebrate known as the Sea butterfly. On Namibia’s infamous Skeleton Coast, three hungry lioness sisters discover this coast for the first time in 40 years and try their luck on hunting a huge colony of seabird at night. A pregnant southern right whale reaches her 5000-mile journey’s end at Peninsula Valdes of Argentina to reunite with her pod while giving birth to her newly-born calf. In British Columbia, a terrestrial garter snake takes the plunge into chilly waters in search of a meal. In tropical Raja Ampat of Indonesia, the coral reef is sheltered by dense mangrove trees that are salt-tolerant and rooted in the seabed, providing a unique opportunity for archer fish, which use jets of water-like arrows to shoot down insects from high above. The flock of Caribbean flamingos settles within the shallow lagoons of Mexico’s Yucatan to nestle their chicks, using hypersaline pools, while struggling to endure the coastal storm. Coasts are the front line in our changing world. Increasingly unpredictable storms, such as hurricanes, and rising sea levels are urgent threats to those who make their homes near the coast, including nearly 40% of the world’s human population. On Raine Island that lies far from Australia, tens of thousands of female green sea turtles come ashore to nest at night to lay their eggs, but some are stranded by the ebbing tide at day time due to their exposure to sun heat and exhaustion. However, most of the sea turtles manage to escape via tidal waves. The island is on borrowed time. This, the world’s largest green turtle rookery, is set to disappear beneath the waves.

In The shallow seas of the tropics, the deadly lionfish was devoured by a clown frogfish which uses a fishing rod attached to its head to detect prey. Away from the tropics, in the cold waters of North America, a young horn shark ventures across forests of giant kelp while evading Giant sea bass and larger sharks. But the real danger is buried beneath. A young horn shark unwittingly stumbles into the ambush of an angel shark and uses its spine for defense. During Winter, storms ravage the Kelps and rip them from the seabed, casting them away into the open ocean. Out in the big blue, the floating kelp becomes a vital lifeline for animals such as flying fish, which use them to lay their eggs. But they must lay thousands because these eggs are on the menu for hungry blue sharks. Life in the vastness of the open ocean relies on these islands of seaweed, but today they are being replaced by something altogether different – plastic. Every year, 12 million tonnes end up in the ocean. It is lethal to many, but some animals are learning to take advantage of these plastic rafts. A male Columbus crab settles on a fishing net while encountering a female crab riding on a Loggerhead sea turtle. Even though Columbus crabs are poor swimmers, the pair settles on a passing turtle which provides a permanent home for them. In return, the crabs provide an onboard grooming service, a relationship that works so well that these turtles are often home to a devoted Columbus crab couple. Finding a partner in the ocean is not always easy. In the Sea of Cortez, mobula rays perform astounding acrobatic leaps to attract other rays, resulting in a gathering of vast numbers. All the noise, however, attracts a family of specialist ray-hunting orca that have a unique strategy to catch these fast and agile animals. The least-known parts of the ocean are its great depths. To venture there require specialized vessels to withstand the crushing pressure. Within the depth of the ocean floor, sunlight fades where life thrives as an alien world, encountering a massive siphonophore, longer than a blue whale, and a gulper eel with huge jaws that can engulf prey larger than its own body. At two miles down upon the seabed, the temperature has dropped to near freezing, so cold that the eggs of a mother pearl octopus (muusoctopus robostus) would take over ten years to develop. She heads to a special place where warm water escaping from the seabed creates a thermal spa. She is joined by 20,000 female octopuses, all here to raise their eggs – the largest-known gathering of octopuses on planet Earth. The warm water speeds up her eggs’ development, but it will still take two years and in that time this devoted mother will not leave them, not even to feed. It is an extreme effort that will eventually kill her. In today’s ocean, animals are having to compete with us. Off the coast of Chile, hundreds of South American sea lion, attracted by shoals of anchovies, have learned clever techniques to raid fishermen’s nets – which they now do in their thousands, but it comes with a huge risk. As the net is drawn in, the sea lions must get out quickly, while others remain trapped as the fisherman releases them. Sadly, the inexperienced young pups didn't survive this experience, and some paid the ultimate price. Animals have evolved in remarkable ways to cope with the demands of life in the ocean. But can they now adapt to the new challenge of living alongside us?

In the baked Namib desert, a pair of ostriches raise their family in the searing heat to keep them safe from predators – but time is ticking as the chicks begin to hatch. Outside of the egg, the newborns won’t survive long in these temperatures, but not all of the clutch hatch at once. For the whole brood to survive, the parents need to time their departure perfectly, but tragically they are forced to leave behind a single unhatched egg. As the family depart, the newborn emerges and the lone chick wanders the vast Namib desert calling for its family and successfully reunited. In Australia, the male spotted bowerbird prepares his courtship for female during the raining season but the rain hasn't arrived. As climatic change causes deserts around the world to expand, dust storms towering up to a mile high and travelling at speeds of up to 70mph overwhelm entire cities in an instant. In the dried river valley of the Erongo region, life exists in a world with almost no water, and it drives one troop of desert Chacma baboons of on a continual quest to find it. A young mother who is low in the pecking order must battle for her right to drink – her newborn’s life depends on it. Without water, her milk will run dry. Where rain falls regularly, it can transform a desert, turning it into one of earth’s most productive landscapes – grasslands. Grasslands support the biggest concentrations of large animals on the planet. This wealth of life, in turn, attracts predators. Leopards are the most adaptable of the big cats, and a handful of special individuals have learned to hunt by hiding and leaping from treetops, some higher than the roof of a two-storey house. Their lives depend on them getting this unique game of hide-and-seek right, and when they do, their prey doesn’t see them coming. The female Leopardess manages to use its hunting tactic to prey on Impala. Grasslands are one of the most widespread habitats on earth, and in the frozen north of Eurasia, a herds of alien-like saiga antelope fight for their chance to win mating rights. Seventy percent of rutting males die every year in battles that have been taking place since the ice age. Closer to the equator, a diverse grassland found in the Cerrado region of Brazil provides the richest grassland ecosystem on earth and home to the rare, fruit-eating maned wolf. The glimpse of the maned wolf nurturing is recorded inside the den where a mother raises her three puppies, but their future is uncertain. The fire suddenly ravage the area but miraculously it didn't reach the den. The Cerrado is a vitally important grassland – home to thousands of species of plants and animals found nowhere else – and it is in danger of being lost forever. In central Africa, one of the world’s most spectacular wildlife gatherings is testament to what can happen if we help protect these precious ecosystems and allow nature to restore its own balance.

In the heart of the Costa Rican rainforest, a little-known spectacle unfolds above a very special pond. Up to ten thousand gliding tree frogs – the world’s largest known gathering of its kind – descend from the canopy for the most important breeding event of the year. It will only last a day, and with males outnumbering females nine to one, competition is fierce. This is a party you don’t want to be late for.

Meanwhile, in Sri Lanka, as the dry season reaches its peak, the last remaining waterhole for miles around becomes a magnet for a different animal: mugger crocodiles. Giants up to five metres long lurk beneath the surface, waiting patiently for thirsty chital deer to approach the waterhole for a drink. But catching their prey is no easy feat and requires them to do something extraordinary. Documented nowhere else, these crafty crocodiles have learned how to exploit their prey’s need for fresh water - by creating traps.

Nestled amongst flowering water lilies, newly hatched african jacana chicks learn a vital lesson – how to ‘walk on water’. Their oversized feet - almost double the length of their body – make for a wobbly start, but their dedicated father will do whatever it takes to keep them safe during the most vulnerable stage of their life.

One of the biggest challenges of living in a freshwater world is its dynamic nature. It can appear, vanish or transform rapidly. Survival in these dynamic environments hinges on adaptation. In the Okavango Delta, the arrival of the great annual flood poses a significant challenge for a pack of five African wild dogs. On dry land, they are one of the continent’s most successful hunters, but as their hunting grounds turn to swamp, they must find an innovative way to master this water world.

Meanwhile, millions of goby fish on the remote volcanic island of Bioko prepare for a perilous journey. After months feeding out at sea, they return to fresh water to breed. The safest place to lay their eggs is where ocean predators can’t follow – at the very top of a 30m waterfall. Surely an impossible journey for a fish only an inch long, and one that will require a bizarre physical transformation.

In a few rare places, like Lake Malawi, fresh water has remained a consistent presence for millions of years, resulting in a dazzling diversity of life. Here, over a thousand unique fish species thrive - more than any other lake on earth, but competition in these crowded waters is intense. To survive here takes ingenuity. Meet Nimbochromis livingstonii - a master of deception that tricks other fish into thinking it's dead.

Fresh water is vital to life, yet it is a finite resource. Of all the water on earth, only 2.5 per cent is fresh and most of that is locked up as ice or hidden deep below ground. In fact, less than one per cent of fresh water is accessible.

Humans rely on fresh water for drinking, agriculture, irrigation, industry and power. Throughout history, we have devised extraordinary means to ensure it is always available for every demand, fostering the dangerous illusion that it is infinitely abundant. Yet today, two-thirds of our world’s great rivers no longer reach the sea, and in the last 50 years, freshwater species have seen an 83 per cent decline globally – a faster decline than that of species in any other habitat.

From the temperate rainforests of Canada, where rarely seen Kermode bear fish for salmon, to the teak forests of India, where a whistling dog pack work together to bring down prey three times their size, the forests of planet Earth are full of unseen connections.

To stand out in the misty mountainous forests of China, male tragopan have developed a comical dance routine, whilst in the dense tropical rainforest, treehoppers form surprising alliances to fight off assassin bugs, and an oriental pied hornbill pair go to incredible lengths to protect their young.