The reality series that challenges a group of volunteers to survive in the wilderness returns. However, this time there are 24 volunteers split into two completely separate and competing groups.

Suzanne focuses the minds of the Cray tribe on obtaining food, while - unbeknownst to them - twelve more participants have just arrived at Wood Camp two miles East of the lake.

After recovering from the shock of discovering they are not alone, the two tribes agree upon a pact to share the fishing gear and split the catch 50/50. But the Crays try to poach star fisherman, Dan, from the other tribe.

Things begin to heat up in the battle for survival as John orders the Snake tribe to move up to the Hunt camp only to find that the Cray tribe have already taken all the tools and stripped the trees of fruit and nuts.

Two weeks into the experiment things go disastrously wrong for both tribes. A storm forces the Snake tribe to move into their rivals' camp where health concerns, homesickness and food poisoning weaken the Crays' position.

After living on nuts, fruit and crayfish for two weeks, the two tribes agree to a joint hunting party. There is discontent with John's leadership of the Snake tribe, prompting a member to defect.

As hunger takes its toll on the libido of the stone-age men news of a baby rocks both tribes. Jay is allowed to take an urgent call from home. It�۪s his first contact with the outside world in six weeks. In tears he leaves the experiment and heads home to his girlfriend and a surprise. But he�۪s not the only one crying. George, abandoned as a baby, and brought up in a childrens�۪ home hasn�۪t cried for over 40 years. Can anyone return from this experiment quite the same as they were before?

Tension grips both tribes as stone-age Adonis, Dan Evans, gets close to a deer and takes aim. Desperate for protein after weeks of eating mostly fruit, nuts and cray fish another dusk-time hunt is underway. Both tribes agree to work together to secure a kill. But the Snake tribe betray the trading pact on sharing big kills 50/50 and keep a 13lb fish for themselves, will the Cray tribe take revenge when Dan finally brings down a young deer? Will the deal forged when the two tribes first met finally collapse?

Three new arrivals in the remote wilderness cause a rift in both tribes as Dan Evans threatens to eat one of them causing his first fall out with tribe leader Suzanne. Keeping goats was a key moment with our stone-age ancestors as they moved from hunter gatherers to become farmers. But the Snake tribe and Cray tribe are hungry and drinking goats�۪ milk is no substitute for eating meat. Will Suzanne save the goats or will chief hunter Dan Evans get the roast goat he dreams about? And a surprise return doesn�۪t please everyone.

As the experiment comes to an end Dan Evans worries his ex-girlfriend will have found another love. Realising she�۪s the one he makes plans to woo her once more, but will he be too late? Will the stone- age experiment have changed him enough to win her back? Aimee gets a shock when she gets on the scales, Sam promises never to hide behind a smile, John vows to show women more respect and George declares the experiment has lit an emotional ember within him. Will anyone return from 10000BC quite the same as they were?