Twelve brave souls take on their first XL challenge in the Colombian Badlands. Survivalists must battle disease-carrying insects, scorching heat, six-foot caiman and stalking jaguars. In this unprecedented challenge, they must trek 40 miles in 40 days.

Adam, Heather and Sam score a massive protein win, but the trek through Colombia's badlands puts the team at risk. Chris battles a mystery illness. As tension rises, Nathan reveals a secret to his partners. The Proving Grounds send a survivalist home.

Malorie and Shell set their sights on an elusive caiman while Adam and Heather build a raised platform shelter to save Sam from ant attacks.

A newly formed tribe quickly works together to stalk andhug a caiman. The pressure to trek 40 miles to extraction pushes two teams to make risky migrations. A survivalist is on the brink when medics discover parasites in their digestive system.

A massive food win buoys Terra and their whole team. On the heels of a caimanhug, Malorie sets her sights on a bigger prize. Heather is shocked when Adam tells her he has not been sharing food. A scorching migration could end Heather's challenge.

Far from extraction, Kaiela leads her team on a punishing trek that puts her challenge at risk; Adam and Heather's smoldering tension makes the new camp choose sides; desperate for protein, a risky survival choice pushes Heather to her breaking point.

The remaining survivalists join forces; when the group splinters to hunt resources, it leads to a big protein win but creates tension between Lynsey and Terra; Nathan uses a primitive cooking method to maximize the meat.

Facing an unprecedented two-day extraction, the final eight survivalists hunt, fish and trap potential food; an emergency overnight in the jungle causes fears and tensions to flare; Malorie's struggles cause medics to step in.