After being dropped off on the island by Bear, the men are in danger of being overwhelmed by the tides. Battling through the dense undergrowth, the enormity of the task ahead dawns on them. As they try to get to know each other, daylight is quickly fading and tempers fray as doubts set in during the search for shelter for the night. With dehydration and hunger taking hold, the men are up against it. They need to find water and make fire or their time on the island will be over. The battle for survival is on.

It's been 48 hours since the men had a meal and hunger grips the group. The race is on to bring food back to camp before they become too weak to hunt. The men take greater and greater risks in the pursuit of vital calories, desperate to seek new ways to chase, trap and outsmart the island's elusive wildlife. Ryan lashes out in anger and Craig is left deflated. And then they come face to face with one of the island's most fearsome predators - the caiman crocodile.

With the men losing weight on a diet of just 300 calories a day, Ryan heads off alone in search of food. But without water, he soon finds himself lost and in imminent danger. With Ryan's actions now affecting the whole group, the men have a choice. Do they bring him back into the fold? Or do they cast him out?

Three weeks into their survival experience and the group is barely getting by on a meagre diet of snails and coconuts. Willing to take ever greater risks for food, Mike and Chris battle with dangerous tides, while tempers fray as it appears that not everyone is pulling their weight. Frustrated by their failure to find another caiman croc, a hunting party risks a trip to the treacherous mangroves at night.

The men enter their fourth week of living on the island with the group hungry and divided. They elect an island leader. But will everyone back him? With island life starting to fall apart, even when a stingray arrives in the fishing nets, arguments follow close behind. But as their time on the island draws to a close and a return to civilisation beckons, there are moments of redemption for some.

Bear Grylls visits the men at the end of their stay on the Island to explore how they coped and how the experience has affected them. Bear also reveals the secrets of how the show was made, with a unique behind-the-scenes look at managing the medical risks to maintaining camera kit in extreme conditions. Bear gets to see first-hand how the men have been living for the past four weeks. He tours the camp and reflects with the men on their personal approaches to surviving. When pushed to the very limit, what did they learn about themselves and each other?