It's all about families in the new edition of The Biggest Loser, which features four husband-and-wife teams and four parent-adult child teams trying to lose weight through diet and exercise as they compete for a grand prize of $250,000. Trainers Bob Harper and Jillian Michaels fly around the country, surprising their teams with the news they've been chosen for the show. Then it's off to The Biggest Loser ranch in California, where the contestants get a wake-up call from the show's doctor about what ages their bodies really are vs. their chronological ages because of obesity. Then the eight teams compete in their first challenge -- and the lucky winner gets immunity from this week's elimination. Alison Sweeney hosts the hit weight loss series.

This week, the contestants take a road trip to one of the most beautiful places in the world - the Grand Canyon! On the way there, they stop by a convenience store for a temptation challenge with host Alison Sweeney that will provide the winning team a much more luxurious trip for their scenic getaway. Once they arrive at the Grand Canyon, they have to figure out how to work out with no gym and no trainers. Later, the family teams compete for an amazing prize in a kayak challenge on the Colorado River before heading back to the ranch, where medical problems threaten to sideline one contestant. Then a surprise shake-up at the weigh in makes for the most difficult and emotional elimination so far.