From the roughest seas to the crystal clear waters of the Florida springs, David Attenborough swims with sea otters and dives with manatees, as he follows those mammals who, millions of years ago, left dry land and returned to the water to feed.
Otters are playful, adaptable and champion swimmers - they've captivated cameraman Charlie Hamilton James for the last 25 years. He's filmed them more than anyone else and now, through the eyes of three orphaned river otters, a set of groundbreaking experiments and some incredible wild encounters, Charlie wants to reveal their survival secrets and exactly why he believes they're so special.
In New Zealand the travellers make their way through one of the most dramatic landscapes in the world. They are on a journey to find the last remaining kakapo, a fat, flightless parrot which, when threatened with attack, adopts a strategy of standing very still indeed.
With coastal mangrove forests, seagrass beds, and vibrant coral reefs, the Florida Keys are home to a wealth of underwater environments, all connected by what scientists have dubbed the 'Corridor of Life.' Take a journey through the vital underwater sanctuaries that preserve these delicate ecosystems.