Fifteen contestants, including "American Idol" winner Ruben Studdard, begin their weight-loss journeys in the premiere of Season 15.

The teams learn that only one member's weigh-in will count for the week, and the representative is chosen by a roll of the die. Also: The players compete in a water-bucket race; a contestant receives a troubling health update; a player connects with a family member; and one of Season 14's child ambassadors revisits the show.

The contestants bid on gym equipment in an auction. Later, one player discusses her difficult childhood; the contestants contact their family members; and Season 12 contestant Vinny Hickerson makes an appearance.

The contestants must scavenge through a pumpkin patch in search of immunity, but temptations lurk around every corner.

Last season's kid ambassadors Biingo, Lindsay and Sunny return to the ranch and are joined by the White House Senior Policy Advisor on Nutrition, Sam Kass, for a fun cooking challenge with the contestants. Well aware that kids are often the toughest food critics, the red, white and blue teams race against the clock to prepare a nutritious and tasty dish that will be a hit with the kids - and earn the winning team members an incredible prize. Also this week, one team works out with a very special and inspiring group of women who have survived or are battling cancer. Later, it's time for the weigh-in and saying goodbye to another contestant

It's a busy week at "The Biggest Loser" ranch, which kicks off with a fun bouncing ball challenge that will award members of the winning team a welcome cash prize. All of the contestant take an emotional walk down memory lane watching their casting audition videos, reminding them why they are at the ranch -- and how far they've come in just six weeks. Ruben and Dolvett visit music icon and 16-time Grammy Award winner David Foster at his home, where Ruben isn't the only one stepping up to the microphone. And the show's most recent "Biggest Loser" winner, Danni Allen, stops by for lunch and a pep talk with the contestants. Then it's time for another tense weigh-in, where one more contestant will face elimination.

The contestants celebrate Thanksgiving week with a special challenge - racing to load boxes of Thanksgiving food into trucks headed to help tornado victims in Moore, Oklahoma, where one player has a special connection. Members of the winning team are very thankful for their prize - a holiday dinner shared at the ranch with loved ones flown in for the celebration. Emotional reunions follow, as the winning team, their trainer and their family members gather for a Thanksgiving feast and share what they are most grateful for. Also, one player gets encouragement from his trainer to talk to his family about a long-kept secret, and the show catches up with one of season 14's child ambassadors, Sunny, to see how she is doing today. Then it's time for weigh-in and another elimination, which leaves one trainer giving a very tearful and emotional farewell to one of their players.

Alison drops a bomb on the contestants: this week, another person will be going home. Before there's time to freak out, she informs them the one person chosen to go home will represent his or her entire team at next week's weigh-in and take the team trainer home for the week. A massive wheel with the contestants' faces on it is spun and the lucky/unlucky winner is... Jay from the White Team! Although Jillian is less than thrilled to go to Farmington, Missouri for the week, Jay is ecstatic to see his family again. He's greeted by a packed room of friends and family.

The contestants meet in a diner to answer questions about obesity, and the losing team must work in the eatery for a week. Meanwhile, a trainer helps one of the players work through personal obstacles; and a contestant's family get on a healthy track.

The contestants meet Alison for this week's Ring of Fire Challenge. Before the challenge begins, Alison informs the contestants that the competition is moving to singles. Once they've received their individual jerseys, the competition begins. The contestants must hold a 20-foot metal rod in a ring of fire as long as they can. The bar weighs 20% of the contestant's weight, and they're competing for a one-pound advantage. It's a respectable prize, and all of the contestants are eager for a big win.

The season's eliminated contestants have returned for a Second Chance Weigh-in. Each of the contestants will step on the scale, and the contestant with the highest percentage of weight loss is back in the competition! Hap is already eliminated, but Matt is still in the running when the eliminated contestants hit the scale.

The contestants arrive in Park City, Utah to begin their week of training with Olympic athletes. They meet with Dolvett, who introduces them to eight-time Olympic speed skater Apollo Ohno. Apollo introduces the contestants to the Olympic training center and gives them a few tips on handling the psychological aspects of training.

The contestants meet with stylists Tim Gunn and Ken Paves to get new styles for their new looks.

The stakes are higher than ever when the five final players compete in a "Biggest Loser" first -- a sprint triathlon, requiring them to swim a mile, bike 12 miles and run three miles. The triathlon winner will secure a coveted spot as a finalist, as well as a brand new Ford Fusion. Then it's an emotional trip down memory lane as the contestants watch footage of their journeys with their trainers, and see firsthand how far they've come since arriving on the ranch. Later, it's time for the last weigh-in before the finale, where two players will fall below the red line and go home, and two more will become finalists, joining the triathlon winner to compete for $250,000 and the title of "The Biggest Loser" at the season 15 finale.

In this must-see, exciting live finale, the 15 contestants from this season return for a special reunion and a chance to weigh in one last time - and show America how much weight they've all lost since beginning their weight-loss journeys. Those who have been eliminated will compete for the $100,000 "at home" prize. Then it's the moment viewers have been waiting for, when one of the three finalists will be named this season's "Biggest Loser" and win the coveted grand prize of $250,000.