The contestants are grouped by age and must choose their trainer in the Season 12 premiere. Tennis star Anna Kournikova and fitness expert Dolvett Quince join Bob Harper to make up the trio of trainers for the season.

Gym-time restrictions are put into place, allowing each team only two hours a day to work out. Elsewhere, the contestants receive health evaluations from Dr. Huizenga, who delivers particularly shocking news to one player; and the teams move a ball through a maze during a challenge.

The players compete for Super Bowl tickets during NFL week at the ranch. Pros Clay Matthews, Drew Brees and Tony Gonzalez head up a football-throwing challenge, while Tim Tebow, Shawne Merriman and Eric Dickerson conduct last-chance workouts.

Former contestants Hannah Curlee, Adam Hurtado and Marci Crozier return to offer inspiration to the teams. Also: The players battle the elements during a challenge in order to win letters from home; a player tries to conquer his fear of the water during a pool workout.

A player goes home and takes a trainer along for the trip. But the prize comes at a cost: the player's weight is the only one that counts for the team at the weigh-in. Elsewhere, the contestants at the ranch navigate a maze to fill a cylinder with soda; and a trainer lashes out at a player who hides behind humor.

- For Halloween, the contestants face a crazy candy temptation and a very spooky challenge, while host Alison Sweeney and trainers Bob Harper, Anna Kournikova and Dolvett Quince get in the spirit by dressing up in Halloween costumes. First, the contestant

The contestants swap teams and trainers after a calorie-counting challenge, and the realignment causes some tension. Later, the new teams face their first challenge together; and the trainers hold last-chance workouts away from the ranch.

This week, only one contestant's weight will count for each team, and trainers Bob Harper, Anna Kournikova and Dolvett Quince get to choose which player will represent their teams. The competition heats up with a cooking challenge in which players and their trainers have to race against the clock to prepare a healthy and delicious low-calorie dish for two special judges - season 11 'Biggest Loser' winner Olivia Ward and 'Biggest Loser' cookbook author Devin Alexander. Prizes for the winning team include something very special from home. Dr. Huizenga drops by with a special medical guest to visit with the players and give one contestant some very welcome news. And later, the weigh-in reveals whether each trainer chose the right person to represent their team before an elimination leaves one player feeling very betrayed.

The players compete in a pentathlon to win immunity at the weigh-in after the teams are dissolved. Speed skater Apolo Ohno surprises the contestants by coaching them through the final event. Elsewhere, a trainer helps a player deal with trust issues.

The trainers prepare Thanksgiving dinner for the players, who also face a temptation challenge with a three-pound advantage prize for the winner. Elsewhere, a tough challenge requires the players to climb one mile on Jacob's Ladder treadmills.

In this eagerly-anticipated makeover episode, the five remaining players head off to a luxury spa to get pampered before shopping for stylish new clothes in Beverly Hills with fashion maven Jeannie Mai. Then in-demand Hollywood hairdresser Ken Paves crafts stylish new looks for the contestants before a limousine whisks them away to see Cirque Du Soleil's 'Iris.' But before the show begins, each player gets a heartwarming reunion with a loved one flown in to celebrate their big day and see their amazing transformation. Later, back to reality and the ranch, the contestants weigh in and one more is eliminated, leaving the final four players of the season.

The stakes are higher than ever when all the contestants return to the same spot where they had their first challenge to compete in a marathon. For the first time in the show's history, the contestant who wins the race automatically becomes a finalist, eligible to compete for the 0,000 grand prize. But there's extra incentive because the first five players who finish the race will also get to split ,000. The only way to guarantee a spot in the finals is to either win the marathon - or be one of the contestants who stay above the red line at the weigh-in. In the end, the three finalists of season 12 will be revealed.

In this must-see, exciting live finale, the 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 0,000 '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 0,000!