The final four contestants go home to reunite with family and friends, and learn that when they return to the ranch, they'll face their toughest challenge yet - running a full (26.2 mile) marathon. It's a daunting challenge, but cheering them along the way will be some familiar faces from the previous season -- season seven winner Helen Phillips and finalists Tara Costa and Mike Morelli, plus a surprise visitor to cheer Rudy on. Later, it's the very last "last chance workouts" with trainers Bob Harper and Jillian Michaels before a final weigh in determines who the two definite finalists will be - and which two contestants fall below the dreaded yellow line, leaving America to vote which one will be the third finalist to compete for the grand prize of $250,000.