Castaways get the biggest reward of the season with surprise letters from home; balance and dexterity are tested at a crucial immunity challenge to guarantee a spot in the final six.

The stakes could not be higher at a crucial, muddy immunity challenge; castaways must spark a win or flame out at a fire-making showdown to earn their way to the final three; one castaway is crowned Sole Survivor and awarded the $1 million prize.