David Attenborough returns to the island of Madagascar on a very personal quest. In 1960, he visited the island to film one of his first ever wildlife series - Zoo Quest. Whilst he was there, he acquired a giant egg belonging to an extinct bird known as the 'elephant bird' - the largest bird that ever lived. It has been one of his most treasured possessions ever since. Fifty years older, he now returns to the island to find out more about this amazing creature and to see how the island has changed. Could the elephant bird's fate provide lessons that may help protect Madagascar's remaining wildlife?
Using Zoo Quest archive and specially shot location footage, this film follows David as he revisits scenes from his youth and meets people at the front line of wildlife protection. On his return, scientists at Oxford University are able to reveal for the first time how old David's egg actually is, and what that might tell us about the legendary elephant bird.

Morgan Freeman narrates Island of Lemurs: Madagascar, the incredible true story of nature's greatest explorers - lemurs. Scientist Patricia Wright has a passion for preserving the life of one particular creature: the lemur. These lively animals found in Madagascar face all sorts of threats, just like so many other animals in a world in which they are increasingly crowded out by humans. Her passion for the subject is compelling and plainly evident, but it's the silent testimony of the animals themselves that really makes the case. Countless hours of footage are trimmed down to create this tapestry depicting the lives of these creatures of remarkable intelligence and ingenuity. Their daily routines and extraordinary adventures are awesome to behold, as is the way that the community functions. A full immersion into the world of the lemurs means great insights on these unusual animals.

In late Cretaceous Canada, in what will be known as Dinosaur Provincial Park, a Daspletosaurus stalks a Chasmosaurus in a forest, but loses the element of surprise and is forced to retreat. The Chasmosaurus comes across a younger Daspletosaurus, before being ambushed by a group of the tyrannosaurids. The episode then cuts to the high Arctic, where Edmontosaurus are hunted by a large species of Troodon. The theropods attack at night, separating a juvenile from the herd and severely wounding it, only to be driven away by an adult. In the morning, they return to eat the carcass of the juvenile, which died during the night. The episode returns to the Daspletosaurus, who chase and bring down the Chasmosaurus. The larger adults bully the youngsters off the carcass, forcing them to wait until they have finished. The episode then cuts to Madagascar, where a mother Majungasaurus (an Abelisaurid) and her two offspring chase a group of Rahonavis off a carcass. However, they are temporarily driven off themselves by a male Majungasaurus. But, after he steals some food from one of the young, the female attacks him, before she and her young cannibalise his body. The episode returns once again to North America, where the Daspletosaurus are waiting for the annual migration of Centrosaurus. They attack during a rainstorm, killing some of the ceratopsians. The Centrosaurus make it to a flooded river and begin to swim across, and although many make it to the other side, some are caught by giant crocodilians or are severely wounded by floating debris and thus drown, or drown for unseen reasons. In the morning, the carcasses attract scavengers, including the Daspletosaurus. A montage is then shown of Daspletosaurus and Majungasaurus, the narrator saying that together, the tyrannosaurids and abelisaurids were the last of the killer dinosaurs.

The world's deserts are lands of extremes that force animals to come up with ingenious ways of coping with hostile conditions, giving rise to the most incredible survival stories on earth. A pride of desert lions are so hungry they risk hunting a giraffe several times their size, while male sandgrouse fly 120 miles each day to the nearest waterhole and dice with death to collect water for their chicks. Filmed for the first time, a tiny bat does battle with one of the world's deadliest scorpions, and in Madagascar, a locust swarm of biblical proportions is seen as never before.

Jungles provide the richest habitats on the planet - mysterious worlds of high drama where extraordinary animals attempt to survive in the most competitive place on earth. Flooded forests are home to caiman-hunting jaguars and strange dolphins that swim amongst the tree tops, while in the dense underworld, ninja frogs fight off wasps and flying dragons soar between trees. Acrobatic indri leap through the forests of Madagascar, while the jungle night conceals strange fungi and glow-in-the-dark creatures never filmed before.

The Taiga forest, on the edge of the Arctic, is a silent world of stunted conifers. The trees may be small but filming from the air reveals its true scale. A third of all trees on Earth grow here and during the short summer they produce enough oxygen to change the atmosphere. In California General Sherman, a giant sequoia, is the largest living thing on the planet, ten times the size of a blue whale. The oldest organisms alive are bristlecone pines. At more than 4,000 years old they pre-date the pyramids. But the baobab forests of Madagascar are perhaps the strangest of all.