Castaways hover on the “Edge of Extinction” in an all-new twist, and four returning players attempt to bond with their new tribemates. Also, castaways tackle a giant puzzle in their first immunity challenge of the season.

The first castaway is stranded all alone on "Edge of Extinction." Also, first-time players bond together in an attempt to get a returnee out of the game.

Teamwork is the key to success in an all-new immunity challenge. Also, two castaways attempt to get along while trying to survive.

Castaways drop their buffs and switch things up, and Edge of Extinction heats up when an eliminated castaway has to face people they blindsided.

The castaways' mental toughness is tested on the Edge of Extinction, and targets begin switching from one castaway to another when weaknesses are exposed.

Alliances are tested after a highly anticipated merge between tribes. Also, one castaway can rest easy after winning the first individual immunity challenge of the season.

The puppet master attempts to pull the strings on other castaways, and one castaway struggles to find balance at an immunity challenge after exhaustion takes its toll.

Tribal Council heats up, and castaways strategize until moments before the vote. Also, concentration is key at a classic immunity challenge.

Two tribal councils in one hour, and a surprise advantage may pay off for one castaway's game.

Another blindside could be in sight after alliances start to crumble. Also, one castaway comes out on top after a crucial immunity win.

One castaway gets caught red-handed rummaging through someone's bag at camp. Also, castaways battle to win reward in the form of love when family members pay a visit.

Spirits are lifted when castaways living "on the edge" read letters that they wrote to themselves before starting this adventure. Also, the final seven castaways battle for immunity during a tough puzzle challenge.

After 39 emotional days, one castaway will take home the $1 million prize and earn the title of Sole Survivor. One castaway's game will unravel, and someone will get a chance to return to the game, when castaways "living on the edge" go head to head on the two-hour season finale.

The castaways reunite in Los Angeles to discuss the season. Jeff Probst hosts.