On a deserted island, survivalists are marooned with no map or tools.

Two teams score food wins but must process the kills without knives.

Heather needs to move camp, but the grueling trek could break Andrew.

Medics intervene when a survivalist consumes toxic fruit.

After an emotional reunion, Na'im vows to get Rachel to day 21; a group must migrate through a croc-infested swamp; Bulent finally comes nose-to-snout with the elusive pig he's been hunting; a survivalist is forced out of the challenge.

Bulent struggles with uninvited guests and scrambles to protect his huge meat win; a water migration tests Na'im, Kerra and Justin's raft -- and a mysterious fever puts their challenge at risk; the groups join forces to push north for extraction.

To be rescued, the remaining castaways must hike across jagged, volcanic rock and crumbling cliffs, build a large signal fire, and construct a raft from driftwood and debris; an explosive fight between Na'im and Patrick threatens extraction.