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.

Will explore the strategy, deception and feats of engineering plants use to thrive in the changing weather of different seasons. In the face of conditions ranging from ice and snow to raging fires, survival is often a question of perfect timing - particularly when contending with intense competition and surprising predators.
In this episode, David Attenborough travels to Finland to show one of the most extreme examples of seasonal plant life in the Arctic Circle. He also travels to California to see how climate change is affecting giant sequoias. These ancient trees like all other seasonal plants depend on the predictability of the seasons and our current changing climate threatens their survival.

The third episode of the series is a visually stunning journey, from the earliest lichens and microplants to the imposing dinosaurs and the diversity of life forms we know today. Key moments in Earth's history are highlighted, such as the appearance of arthropods, the development of terrestrial flora and fauna, and the mass extinctions that have reshaped ecosystems.
The documentary not only shows the resilience and adaptability of life on our planet but also highlights the fragility of our ecosystem and the crucial importance of preserving biodiversity for the future of Earth. This documentary is a celebration of life in all its forms and a powerful reminder of our role in protecting this incredibly diverse and dynamic world.