After revisiting the hospital to check in on their progress, the remaining players face off in one of the biggest challenges in "Biggest Loser" history -- they must fly across a ravine on zip-lines and collect flags. One player gets the chance to give immunity to himself or one of his teammates, and his decision ultimately affects his own fate. And a shocking announcement at the weigh-in changes the way the rest of the game will be played. (thetvdb.com)