In this fourth series of epic survival, Bear Grylls maroons two sets of people from two different generations on a pair of deserted islands in the Pacific. Wearing just the clothes on their backs and armed with some basic tools, which generation is better equipped to survive? As the younger generation struggle with the basics of food and water, the older generation appear to be streets ahead. But when their water source runs dry, they urgently need to find a new home. Will they make it to the younger group’s island? And what will they make of their neighbours?