The great flood in the Okavango turns 4,000 square miles of arid plains into a beautiful wetland. Elephant mothers guide their families on an epic trek across the harsh Kalahari Desert towards it, siphoning fresh water from stagnant pools and facing hungry lions. Hippos battle for territory, as the magical water draws in thousands of buffalo and birds, and vast clouds of dragonflies. Will the young elephant calves survive to reach this grassland paradise? The experienced mother elephants time their arrival at the delta to coincide with the lush grass produced by the great flood.
In a TV first, the programme shows the way they use their trunks to siphon clean water from the surface layers of a stagnant pool, while avoiding stirring up the muddy sediment on the bottom with their feet. Lechwe swamp deer, zebras, giraffes, crocodiles and numerous fish and thousands of birds arrive in the delta. And, in a phenomenon never before filmed in the Okavango, thousands of dragonflies appear - seemingly from nowhere - within minutes of the flood arrival, mating and laying eggs. As the flood finally reaches its peak, elephants and buffalo, near the end of their epic trek across the desert, face the final gauntlet of a hungry pride of lions. In a heart-wrenching sequence, a baby elephant is brought down by a lion in broad daylight.

Sex is the key to the immortality of genes, and any tactic necessary will be deployed in the cause of reproduction - even if it's suicidal to the participant. This episode explores many of the most ingenious, complex, and dramatic methods that animals employ to ensure the continuation of their genetic line.

Sir David Attenborough explores the surprisingly vibrant seas that surround the British Isles. The vast watery wilderness around us is over three times the size of our land mass, and yet to many, our oceans remain a mystery. Full of colour and teeming with life, the seas of Britain and Ireland are crucially important to a range of wildlife. This episode goes beneath the waves to uncover the thriving habitats that exist along our 22,000-mile coastline.
In winter, clear evidence of the ocean’s abundance can be seen on a beach in Norfolk. Thousands of grey seals congregate on the shoreline to give birth. Britain and Ireland are home to 40 per cent of the world’s grey seals, and the number being born on our shore rises every year. Once the newly born pups are weaned, the females are ready to breed again, and heavyweight males enter violent, bloody fights to win a stretch of beach, and the females along with it.
Beyond the beach, the vibrant shallows contain several important habitats. Rich beds of seagrass are nurseries for a range of animals, while also acting as very important carbon storage areas. They are also home to one of the strangest fish in our waters, the seahorse. We follow a male and female as they perform a balletic mating dance in the water, delicately entwining their tails. The stakes are high, as these animals mate for life.
In a touching piece to camera, Sir David bids a fledging Manx shearwater chick farewell as it embarks on a 6,000-mile journey across the oceans to South America. There is no better example of how important the British Isles and its abundant seas are to the survival of wildlife worldwide.