The Island with Bear Grylls

Old and young go head-to-head on the fourth of Bear Grylls' survival series. Marooned separately on a pair of remote tropical islands in the Pacific with just the clothes on their backs and a handful of basic tools, which generation has what it takes?

The young generation realizes they've chosen the wrong campsite when rain turns it into an uninhabitable swamp, and they decide to combine with the older group who have set up camp further north.

With old and young now living side by side, the islanders are hoping to hit their stride. But a few weeks into their time on the island, lack of food is an ever-pressing concern, and tempers are fraying.

The islanders face Mother Nature at her most violent and brutal. Having already endured a series of torrential downpours, which have ravaged their campsite, the islanders are unaware that a hurricane is brewing 100 miles to the north.

After four weeks on the island, the castaways have collectively lost almost 30 stone and are increasingly beleaguered as they enter their last days on the island. Karen is suffering more than the rest, with dangerously low blood sugar and diarrhea.

Bear Grylls returns to meet the castaways from the two generations who survived for five weeks and finds out firsthand how they did it. Was it the wisdom of age or the energy of youth that proved most valuable in their attempts to survive?