Two new trainers and a compelling new twist deliver a game-changing season like nothing viewers have seen before when season 11 premieres with twenty-two contestants -- eleven family and friend teams of two. After the first challenge, contestants are given the unprecedented opportunity to choose whether to work out with trainers Bob Harper and Jillian Michaels at the ranch or work out at a secret location with two unknown trainers and get four weeks of immunity. What ensues is a riveting ride of intense emotions, surprising turns and 'can't miss' moments as the two groups fight their weight loss battles separately with two sets of trainers equally committed to giving these players a new lease on a healthier life. The contestants include an Olympic gold medalist, identical twin policemen, a pastor who wants to spare his overweight son from the challenges he faced because of obesity, and a woman who has lost pregnancies because of her weight and wants more than anything to be a mother.

This week kicks off with host Alison Sweeney issuing a challenge to the ranch-based contestants: if they have a higher percentage of weight loss than the 'unknowns' - the contestants working out with the two new mystery trainers -- they'll all have immunity this week. The 'unknowns' fuel the competitive spirit by delivering messages and surprises to the contestants at the ranch reminding them just how tough their competition really is. Then Dr. Huizenga gives sobering news to contestants about their health risks and their real ages vs. their chronological ages, but this time, loved ones from home are involved to really help drive the message home. Later, the ranch contestants' ability to work together as a team is tested when they try to beat the time of the unknowns in a wild bridge-building challenge using rafts. Then a tense weigh-in reveals whether the ranch contestants are safe from elimination, or whether they'll be sending another player home.

The 'unknown trainers' are finally revealed, and both will share their personal stories that led them to 'The Biggest Loser.' Their contestants, 'the unknowns,' confront one player they feel isn't working hard enough, and later, 'the unknowns' and the ranch contestants square off for a pop challenge. The winning player from each group will get a delicious healthy dinner prepared by Chef Curtis Stone, and compete for a coveted 2 lb. advantage at this week's weigh-in. Later, Dr. Huizenga gives 'the unknowns' startling news about their health, and one player is surprised to learn they have the highest percentage of body fat in the group. Meanwhile, trainers Bob Harper and Jillian Michaels single out a few of their contestants to find out what really led to their weight gain, and then the ranch contestants meet host Alison Sweeney for a water-carrying challenge that will give the winner the sole vote at this week's elimination. Later, a surprising weigh-in -- which results in shocking numbers for one team -- disappoints the trainers in a big way, leading to the elimination of one player they feel isn't ready to go home.

The contestants are faced with the 'ultimate temptation' this week when each team enters a room filled with each player's favorite foods. Whoever eats the most calories gets to choose which team will go train with the 'unknowns' and the new trainers. Later, the stakes are high with a calorie-counting challenge that will give the winners what they want most - letters from loved ones back home. The trainers confront a contestant they think threw the last weigh-in, and later, trainer Jillian Michaels puts trainer Bob Harper through an intense yoga workout to show the players what they'll ultimately be able to do once they lose weight. Then one player takes matters into their own hands to try and send a contestant home.

After four long weeks, the 'unknowns' move to the ranch and are reunited with the other contestants, who get to meet the new trainers for the first time. Host Alison Sweeney explains that the ranch contestants will be safe this week if they collectively lose more than 48 pounds, but for the 'unknowns,' they will be facing their first elimination all season. And both teams only get to see their trainers once this week. The 'unknowns' experience some surprises while settling into their new home, and a secret is revealed about how one contestant has lost so much weight. A challenge involving weights shows which team stacks up to be the best, and later, everyone weighs in and finds out whether one or two players will be going home.

It's Valentine's Day on the ranch, and host Alison Sweeney ushers the contestants into a room full of chocolate candies for a holiday-themed temptation. Whoever eats the most chocolate will have the option to trade two players on their team for two players on the other - or to keep the teams the same, and the winner will be a secret. But as teams are divided into red vs. black, the winner's choice causes upset in the house. Later, a five-part relay race challenge tests the players' endurance, speed, agility, strength and knowledge. Trainer Jillian Michaels takes one contestant horseback riding, and one team gets to enjoy heartwarming videos from home before a weigh-in results in a Biggest Loser record being broken and another player heading home.

The two teams of contestants are all tied up this week - literally - in a rope challenge in which teamwork will determine which group of players will get to use the gym this week, and which team will have to be creative and find other places at the ranch to work out. One trainer moves into the house to try and get a contestant to open up, and later, one team wins the chance to block someone's weight on the scale at a wild physical and mental challenge that finds them pushing a train 800 feet while answering food fact questions along the way. Then one player reaches a milestone at the weigh-in before another contestant is eliminated and sent home.

A ball challenge that turns out to be much harder than it looks gives the winning team a big advantage at this week's weigh-in, which is especially valuable given that both a red line and a yellow line will result in two players going home. Trainers Bob Harper and Jillian Michaels try to teach their contestants to push beyond the limits they've set for themselves, while trainers Cara Castronuova and Brett Hoebel take their team for an intense workout at a Mixed Martial Arts gym owned by contestant Rulon Gardner's former trainer, retired UFC heavyweight champion Bas Rutten. Then a weigh-in filled with surprises is followed by two contestants leaving the ranch.

The contestants are excited to hear from host Alison Sweeney that they will all be going home for two weeks. Each player returns home to emotional reunions with friends and family, after which they navigate the challenges of being back in their real lives, facing the same temptations that brought them to the ranch and realizing all of the things they are capable of doing now that they couldn't do before. When they come back to the ranch, they'll compete in a 5K challenge on a treadmill just as they did in the first episode of the season, but this time, they're going to run the 5K all by themselves. And just as before, each will pick who they want to train them - Bob Harper and Jillian Michaels or Cara Castronuova and Brett Hoebel - in the order in which they finish the challenge. Then a few contestants reach milestones at the weigh-in, after which another player is sent packing.

Each team has to pick a team captain, who will have many responsibilities during the week, and only two players from each team can work out with a trainer. The teams first square off in a pop challenge involving 13 tiered cakes, and later, the contestants meet host Alison Sweeney at a mud pit where they have to make their way across the pit while balancing on a step - without touching the mud. Several contestants have heart-to-heart talks with their trainers, opening up more about the individual personal struggles they had before coming to the ranch, and later, another player is sent home following a weigh-in with some surprising weight loss numbers.

Host Alison Sweeney tells the remaining 12 contestants that they will all be on one team this week - the blue team - and they will all have immunity if they beat their weight loss from the previous week. But first, there's a pop challenge in which they have to prepare delicious, healthy, low-calorie meals in under 30 minutes. Chefs Curtis Stone and Lorena Garcia will decide who prepares the best dish, with the winner getting a coveted prize. Later the blue team meets at a rock quarry where they'll have to uncover a buried rope attached to signs with trivia questions. If they answer the questions incorrectly, they will be led in the wrong direction, something all the players want to avoid since the winners get a huge advantage at this week's weigh-in. Later, Dr. Huizenga drops by with impressive medical updates, including the news that one contestant has already reached their goal weight. Then it's time for the weigh-in, when players found out if they all get to stay at the ranch another week - or if they'll be sending one contestant home.

This week, one eliminated contestant returns and the remaining players are split into four teams: red, blue, green and black. Each team will be led by one of the four trainers: Bob Harper, Jillian Michaels, Cara Catronuova and Brett Hoebel. While Bob takes his team to spin class and Jillian takes hers to work out at the beach, Brett leads his group on a hike and Cara heads to a boxing ring and has one of her players fight against a longtime boxer. Later, the four teams square off in a difficult challenge involving ropes and weights, and then gameplay at the weigh-in doesn't turn out the way one contestant expects, and another player is sent home. Alison Sweeney hosts the series.

The remaining four teams square off for a wild pop challenge that involves balancing eggs, and the losing team has to leave the ranch for the week and work with a limited budget to purchase what items they'll need most. Trainer Bob Harper takes his contestants to an inner-city school, where they energize the students with a fun workout and talk about the importance of fitness. Then all the contestants go on a huge Easter egg hunt for 5,000 eggs, including a Golden Egg that comes with a very coveted prize. And later, the players are treated to a sneak preview of the upcoming feature film 'Hop.' Finally, one player reaches a milestone at the weigh-in before another contestant is sent packing.

This week kicks off with a pop challenge in which contestants have to estimate the length of a mile. The winning team gets a night out on the town, Hollywood style, while the other players have to stay behind and clean the ranch. Later, the teams race to light up a 'Biggest Loser' board in a challenge that gives a stiff penalty for the losing team - no votes at the elimination. Then one trainer gets shocking news at the weigh-in, and after an emotional elimination, host Alison Sweeney delivers some very exciting news to the contestants.

The nine remaining contestants arrive in New Zealand and embark on the adventure of a lifetime, starting with a visit to Sky Harbor, a popular tourist attraction known for its breathtaking views. Awaiting them are 51 flights of stairs to climb followed by the adrenaline rush of sky-jumping for contestants and trainers. Then it's on to a 5K challenge New Zealand-style, with the winning team getting an unforgettable helicopter ride to gorgeous Waiheke Island. The trainers take contestants to the Auckland Fish Market, where they talk about eating healthy while travelling abroad, and Jillian has a lively lobster encounter. Later, the contestants charter an American Cup racing boat to sail around Auckland Harbor, and one player with a special connection to New Zealand gets a very generous gift.

The New Zealand adventure continues in Queenstown, where the eight remaining contestants learn from host Alison Sweeney that the game is going to singles. Then a special visitor surprises all of the players with a grand and unforgettable entrance! This week's challenge is river surfing, with the winning contestant getting the coveted prize of immunity plus a helicopter ride to spectacular Milford Sound, one of New Zealand's top tourist destinations. Zip-lining, rock climbing and bungee jumping highlight the rest of their memorable Queenstown experience before a weigh-in sends another player home.

It's 'Favorites Week' on the ranch, and the remaining seven players participate in a favorite past season challenge - pulling a car for a half mile. Popular NASCAR driver Clint Bowyer is there to cheer them on at the speedway, and Tara Costa, the season seven winner of this challenge, returns to compete alongside the contestants for some amazing prizes. Later, popular season nine contestant Sam Poueu and season five winner Ali Vincent put the contestants through a workout in the gym, and also motivate the players one-on-one. Then it's a weigh-in full of surprises, leading to one more contestant facing eliminaton.

It's the eagerly-anticipated makeover week at the ranch, and fashion guru Timballoonn guest stars in the Cinderella-themed makeover as a fairy Godfather to the remaining five players. Tim works his fashion magic helping the contestants pick out stylish new outfits to flatter their new slimmer selves, and celebrity hairstylist Ken Paves crafts incredible new looks for each player, leading to amazing and dramatic transformations. Then they are off to enjoy a magical evening, arriving by horse-drawn carriage at a beautiful castle, where they will enjoy heartwarming reunions with loved ones and be treated to a special private concert by the popular band OneRepublic. And the magic continues at this week's challenge, which finds contestants searching through 50 car-shaped sand castles for the keys to two incredible prizes - brand new Mazda 5s. Then it's time for the weigh-in, where one final surprise awaits the contestants.

It's 'Finals week,' and each contestant will be tested by the trainers to see how much they've really learned at 'The Biggest Loser' ranch, with the winner claiming a big cash prize. The players get a chance to add to their overall test scores by competing against each other in four difference exercises while playing 'The Biggest Loser Ultimate Workout' on Kinect for Xbox 360. Later, the contestants are put to another test with a stair-building challenge involving weighted sandbags. The winner gets a weigh-in advantage that could help determine who makes it to the final four - and who is sent home.

It's down to the final four contestants, and this week kicks off with a fun cooking competition to see who can make the tastiest turkey burgers for a group of kids. Then it's off to the golf course, where season ten winner Patrick House is waiting to cheer the players on as they 'put the weight back on' in one of the toughest challenges of the season. Carrying a heavy golf bag filled with flags weighted for how much they lost each week, each player races from hole to hole, dropping the flags along the way and reminding themselves just how far they've really come. Also, the contestants get to make calls to eliminated players to see how they've been doing at home, and later, they have their final last chance workout at the ranch with the trainers. Then one last 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 0,000.

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. There are four contestants left, but America has voted on the two that fell below the yellow line in last week's episode to choose who will be the third finalist in the game. After America's vote is revealed and the third finalist is announced, the eliminated player will then weigh in with the other eliminated contestants to 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!