After nearly three weeks in the bush, two survivalists have tapped out, most others are making desperate treks across the savannah in search of food. If they can't find sustenance, they'll be forced out of the biggest challenge of their lives.

The 10 remaining survivalists cross the 21-day milestone and enter into uncharted waters. Scarce resources send the survivalists on a collision course. They fight for their lives with a huge electric eel and are visited by a gigantic puma.

With 15 days to go in the 40-day challenge, the ten remaining survivalists - dehydrated and protein starved - find themselves converging at dangerous Piranha Lake where they will they compete over scarce food and water.

After thirty-one days in the Colombian jungle, the pressure is on to get the nourishment they need to survive extraction, but when one member doesn't play by the rules, the future of one group is thrown into jeopardy.

The final, and most difficult, part of the 40-day challenge begins. Jeff & EJ decide to attempt their extraction alone, and relationships grow contentious between both teams as they navigate the treacherous landscape to try and finish the challenge.

The Dirty Dozen survivors from Naked and Afraid XL come together for the first time since their life-changing 40 day challenge. They'll discuss good times, hard times, and try to heal unresolved issues.

In a special one-hour preview, 12 Naked & Afraid veterans prepare for the most formidable survival challenge on the planet - surviving 40 days and 40 nights in the sun-scorched bush of South Africa.

Stalked by lions, hyenas and aggressive crocodiles, 13 all-star survivalists try to survive for 40 days in Africa's sun-scorched Selati Basin. Resources are scarce and when one group scavenges meat, hungry predators stalk their camp.

Two Naked and Afraid super fans get one-on-one intensive primitive survival training with veteran survivalist, Gabrielle, before attempting a full 21-day challenge alongside all-stars Matt Wright and Gary Golding.

Jason Staker builds a shelter capable of protecting against large wild animals and standing up against the elements in the Aspen Grove forest.

T.J. builds a 5-foot elevated tree house capable of keeping his team safe from flash floods in the High Mountain Valley.

Cat builds a 10-foot elevated tree house capable of keeping her team safe from flash floods in the High Mountain Valley.

Joel builds a watercraft capable of carrying his team and supplies across the Alpine Lake.

Tamra builds a shelter capable of keeping her team safe during the heavy rainfalls present in the Spruce Forest, as well as a bridge to grant access across a crucial stream running through the forest.

Matt builds a seasonal hunting camp in the Chalk Creek hunting grounds.