The film explores the eye-opening realm of these creatures to better understand how they evolved. Travelling from the rain forests of French Guiana to the Arctic Ocean, scientists use traditional and cutting edge techniques to examine both modern insects and the fossil record in their search for a single common insect ancestor. Insects are vital to life on our planet, yet almost 40% of known species are in danger of extinction.
Insects are the most diverse group of organisms on Earth. The true number of species is unknown, but some estimates suggest that only a fraction have been identified. They have successfully adapted to every ecosystem on our planet. But insects still harbour many mysteries. Where do they come from? When did they first appear on Earth? How and why have they diversified and multiplied so successfully? At a time when certain insect species are in danger of extinction and there is greater interest in their role within ecosystems, this is the fascinating story of their origins.

Travel back 66 million years to when majestic dinosaurs and extraordinary creatures roamed the lands, seas, and skies in the second season of this acclaimed series narrated by David Attenborough.
After a tropical storm, two Zalmoxes find themselves in a rafting event. On a small island, a monumental display takes place as several Hatzegopteryx ambush a herd of Tethyshadros. A female Majungasaurus hunts a group of Simosuchus. A mother Adalatherium raises her offspring in a burrow, hoping to keep them safe from predators like Masiakasaurus and Madtsoia. A pack of Imperobator pursue a Morrosaurus onto a frozen lake. A male Hatzegopteryx attempts to attract a mate.

Female Isisaurus traverse the Deccan Traps to reach their nesting site. A mixed herd of sauropods and Prenocephale navigate a maze of canyons, but are ambushed by a pack of Velociraptor and a trio of Tarbosaurus. A colony of male Corythoraptor protect their eggs from the scorching sun by day, and a female Kuru kulla at night, who has offpsring of her own.
Trudging through a scorching desert, two young Tarchia find relief at an oasis and encounter an adult twice their size, ready to lay claim. Several Isisaurus hatchlings fall prey to Rajasaurus in an attempt to reach their ancestral home.

Pterosaur hatchlings take flight to leave their island sanctuary, but are targeted by several Shamosuchus. Several Austroraptor hunt garfish and contend for the best fishing spots. A male Beelzebufo attempts to attract a mate, but his endeavor is interrupted by a herd of Rapetosaurus. A male Pachycephalosaurus must put an upstart youngster in his place. Two Tyrannosaurus brothers hunt Edmontosaurus under the cover of darkness.

A female Phosphorosaurus hunts lanternfish under the ocean's moonlit surface. Hesperornis hunt for fish until they themselves are hunted by Xiphactinus. A Mosasaurus hunts a group of Tuarangisaurus. Nostoceras hatchlings are at the mercy of the tides and juvenile Pyroraptor. The young Nostoceras that survived find themselves among Baculites and Diplomoceras in their new seagrass meadow home. A pod of Morturneria sift the muddy seabed in search of food.

A Tyrannosaurus and two Quetzalcoatlus fight over an Alamosaurus carcass. A shoal of Sphenodiscus are ambushed by a Globidens, intent on surplus killing them. At an evaporating lake, juvenile Pectinodon hunt flies while their father hunts Styginetta. Male Triceratops fight and display for the right to mate. A female Nanuqsaurus hunts Ornithomimus to feed herself and her offpsring.