After 160 million years of dominating life on earth the dinosaurs appear as vigorous as ever. Yet closer study reveals there are hidden stresses and the rich ecosystem hides problems. Volcanic activity is high and disease and sterile eggs common. The central character in the program is a female Tyrannosaur that is trying to raise a new brood of chicks. As the program starts, small mammals are already swarming over one nest that she has abandoned and she is looking to mate again. She lives at the base of an active volcano and the migration of local herds has been disrupted by lava flow. She finds a mate and starts a second nest but it needs constant attention, as mammal populations are unusually high. After several months she successfully hatches some of her eggs, but in an attempt to protect the young chicks, an Ankylosaurus kills her.

Set in the mid-Triassic period, when the world was still recovering from a massive extinction that millions of years before wiped out 95 per cent of life. Across most of the Earth lie vast deserts but near the poles the weather in monsoonal. Here life is rebuilding the diversity that once existed. The program follows a small group of animals in a river valley through the dry season. Large herds of the Placerias, an ancient, bulky reptile, feed off the fern prairies. Primitive mammals dig burrows beneath them, small pterosaurs chase insects in the air and an agile little dinosaur called Coelophysis lives on its wits among them. Terrorizing all these creatures is the giant predator Postosuchus, a fearsome land crocodile with a head like a Tyrannosaurus. As the drought drags on, all the creatures are affected by it. The herds dwindle and the mammals lose their offspring.

Throughout the entire time of the dinosaurs there were no ice caps on the poles. In the mid Cretaceous period, thick forests covered Antarctica. Although the climate here was warm, the sun would set completely for two months during the winter and then, for the first time in their history, dinosaurs would have faced ice and frost. The animals that lived here evolved to cope with what was, by dinosaur standards, the most extreme of environments. The program follows a small group of social herbivores called Laellynasaura that live in the forest all year round. It starts with spring as the little dinosaurs survive another long dark winter. As the forest comes alive, the Laellynasaura build nests together and lay eggs. Gradually other dinosaurs migrate down from the north and start to graze in the river valleys.

On a deserted beach lies the dead body of a giant pterosaur, an Ornithocheirus. With wingspans of up to 13 meters, these were the largest flying creatures ever. There is no sign of why this one died but over the course of the program, it is revealed how this King of the Sky met his end after undertaking an epic flight to find a mate. The program picks up several months earlier on a windy cliff edge on the coast of Brazil where the mating season has begun for a bizarre-looking pterosaur, Tapejara, is in full swing. On every ledge the males duck and bob their fantastic red crests to attract a mate. The solitary Ornithocheirus is here too, dwarfing the local inhabitants. He has ended up in Brazil after wandering thousands of miles in search of food but now he has to return home to his own mating ground in southern Europe. His flight takes him up the coast of Northern America.

By the late Jurassic period, dinosaurs dominated the globe and the most widespread group of all was the sauropods. These long-necked herbivores were giants even among dinosaurs, weighing between 20 and 70 tons. This single program spans 12 years, following the hatching of a tiny Diplodocus through her struggle for survival until she reaches maturity and mates for the first time, completing the circle of life. The action opens with a huge mother laying her eggs on the edge of a vast forest. She then abandons them and when they hatch they have to run the gauntlet of every predator in the area as they make their own way deep into the woods and seek the protection of dense vegetation. We follow one female over the years as she gradually piles on the tons, avoiding dangers from hungry carnivores and fire.

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