In the first episode, the tribe is dropped into a remote forested wilderness. Waiting for them is Klint Janulis, an archaeologist and survival expert. He will help them swap their smart phones and modern clothes for animal skins and introduce them to their new home – a Mesolithic-style camp supplied with some basic tools, rations and a pile of flint. To get them started, they are given a freshly killed deer – a sudden reality check for vegetarian Josie. With only hours before nightfall, the tribe have to preserve as much food as possible, dig latrines and make a fire. Hours later, with the fire still not lit and raw meat ready to be cooked, their first night looks likely to be a very cold and hungry one…

Steve tries to get the team not to make the same mistakes that they made when they allowed the deer meat to be wasted. Paul attempt to create a boar trap whilst an unpleasant discovery is made by Kim.

With rations running low and the animal traps empty, Steve organises a fishing party. After trekking for more than three hours the hungry anglers cast their lines, but while they get many bites landing a fish proves to be difficult. Back at camp, hunger claims its first victim as Kym has to have medical help.

Day 8 sees the tribe with only enough rations for another day. When another fishing trip yields little in the way of nourishment, the condition of the tribe forces the survival experts and the producers to decide whether to intervene or halt the experiment.

Ten days in, and the tribe are still desperately low on rations as the cold weather sets in. A freak snowstorm covers the camp in two feet of snow, forcing the production team to consider evacuation.

It is Day 22 of the experiment, and the tribe have returned to camp. An argument arises over how to treat a fresh deer carcass and Steve loses control of the group.

New leader Mel is determined to conserve rations and supplement them with foraged roots, berries and fish, but Paul is determined to go hunting. JP threatens to leave when a meeting is called to discuss his laziness.

Paul and Mike continue to defy Mel and go hunting, but they return empty-handed and collapse with exhaustion in front of a group of the girls. JP demonstrates hitherto unsuspected talents.

With less than two weeks to go until the experiment is over, the tribe are subsisting on half their recommended calorie intake. Leader Mel thinks that they have enough food to last, but Paul is doubtful.

In the final days of the experiment, only five of the original 20 tribe members remain. With the recent shock departure of Paul and Mike still seriously ill, Mel finds the strain of carrying the weaker members is pushing her to breaking point.