Three years after the devastating fire, Lucy Worsley has exclusive access to the Cathedral of Notre-Dame de Paris at a key turning point of the restoration. Work to rebuild and restore the monument is being ramped up in a bid to meet the ambitious deadline to reopen it to the public in 2024. Scaffolding now fills the interior of the cathedral, giving Lucy and the team unprecedented close-up access to every inch of the structure. Lucy meets scientists, historians and craftspeople working to return the 850-year-old Gothic masterpiece to its former glory.
The fire coated Notre-Dame with tons of toxic lead dust, so specialists are now decontaminating the site. Unique access to the stunning rose windows allows Lucy and the stained-glass historians to uncover the mysteries of these enigmatic 13th-century works of art. An unforeseen legacy of the fire threatens to destroy the remaining vaulting, so the team must develop an ingenious solution to save the stonework. The loss of the roof during the fire reveals hundreds of large iron staples embedded in the stone along the top of the walls. And the incredible task of sourcing and cutting two-thousand perfect oaks gets underway to rebuild the world's most complex medieval timber structure - Notre-Dame's extraordinary roof and spire.

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.

In the fourth episode, Dromaeosaurs stalk a hadrosaur herd as they cross a freezing river. Male Ornithomimus raid rival nests to bolster their own. Olorotitan raise their offspring on fertile volcanic fields but contend with biting mosquitoes.
Troodontids hunt mammals flushed out by a forest fire. A juvenile Antarctopelta scours the forest for a new winter den. Within the snow-covered forest, a tense standoff develops between ancient rivals, Pachyrhinosaurus and Nanuqsaurus.

In the last episode, Austroposeidon level trees in search of fresh foliage. A herd of Triceratops journey through a cave to find an underground clay lick. A male Carnotaurus sets the stage for an extravagant display. A female Qianzhousaurus uses an autumn storm to her advantage while hunting Corythoraptor.
A family of Edmontosaurus evade a forest fire, while an Atrociraptor and Ankylosaur reap its rewards. Juvenile Therizinosaurus attempt to climb up to a bee nest. Hatzegopteryx hunts Zalmoxes, and patrols the dense undergrowth and seaspray-battered coastline.

A new era of space is dawning where small satellites no bigger than a shoebox will be deployed not in one or twos, but in their thousands - referred to as satellite swarms. It's been described as the democratization of space. What was once the preserve of governments and superpowers is evolving into a truly global industry. The catalyst for this dramatic change is this new generation of satellites.

The last chapter explains how the 2010s became another lost decade in the fight against climate change – as the move to natural gas delayed a transition to more renewable sources of energy.
Engineer Tony Ingraffea, in the 1980s, helped develop a new technique for extracting gas and oil from shale rock, which ultimately became known as 'Fracking'. It was to unleash vast new reserves of fossil fuels and was promoted as a cleaner energy source. But Ingraffea explains how he later came to regret his work when he realized that gas could be even worse for climate change than coal and oil.
Dar-Lon Chang, a former ExxonMobil engineer, speaks for the first time on camera alleging that as the company increased its natural gas operations, it was not sufficiently monitoring methane leaks that were contributing to climate change. Now, after a year of unprecedented wildfires, drought and other climate-related disasters, multiple lawsuits are being brought in US courts in efforts to hold Big Oil legally accountable for the climate crisis.