In the 10th season premiere, Bob and Jillian travel across the U.S. to meet potential players for this season.

The Season 10 players have finally arrived on The Biggest Loser ranch and they meet with Ali. She tells them they should be proud for making it this far, but now the hard part is staying on the ranch. Ali surprises the players more by welcoming two more players to the ranch, Aaron and Elizabeth as the Yellow Team. Dr. H visits with each of the players and delivers the harsh truth that they are damaging their bodies with food. Dr. H explains to the players how old their health tells him they are, compared to how old they really are. Each player takes the news very emotionally.

One contestant creates tension in the house by expressing a wish to go home; professional tennis player Anna Kournikova gives the contestants tennis lessons before they face a challenge involving tennis balls; another contestant is sent home.

The episode begins with a temptation challenge filled with tons of cupcakes. Alison, always the bearer of bad news, tells the players that there will be both a yellow line and a red line at the weigh-in. Fall below the red, and you're automatically out.

Players who didn't make the initial cut for a spot on the ranch return to weigh in, and the person with the highest percentage of weight loss wins entry into the competition. Later, the contestants are split into blue and black teams and compete in a food-trivia challenge in downtown Los Angeles

Chefs Curtis Stone and Lorena Garcia guide the players during a timed cooking contest. Elsewhere, the blue and black teams face off in a dragon-boat challenge, and the players choose one person from each team whose weight will count at the weigh-in.

The contestants spend a week training with marines at California's Camp Pendleton. Their regimen includes hiking with large backpacks, rifle exercises and an obstacle-course challenge. At the end of the week, Bob and Jillian lead last-chance workouts before the next weigh-in.

The players compete as duos, which are arranged by the winner of a dinner temptation, but the pairings don't please everyone. Elsewhere, Bob and Jillian address the issues that are holding some contestants back. Then, the pairs stack sugar cubes for a challenge before a particularly tense weigh-in.

The players begin competing as singles. Elsewhere, the contestants receive videos from home, a welcome distraction from the speculation surrounding the previous week's elimination, and rally around one player who doesn't receive a video. Also, a balancing test in a pool and a personal milestone for a contestant at the weigh-in.

The players receive makeovers from hairstylist Ken Paves and participate in a photo shoot. Then, they show off their new looks to friends and family during a fashion show. But once they return to the ranch, it's back to work with an endurance challenge that awards the winner a new car. A contestant hits a milestone at the weigh-in.

Gymnast Nastia Liukin leads a stamina-testing surprise challenge. Elsewhere, a player receives good news from Dr. Huizenga; the contestants race while carrying the weight they've lost so far; and two players are eliminated after the weigh-in, leaving the final four competitors at the ranch.

The remaining four players leave the ranch and try to maintain healthy habits at home. After six weeks, they return to the ranch to run a marathon before the final weigh-in. Two finalists are named, and the other two must depend on viewer votes to compete in the finale

After viewer votes determine the third finalist, the winner of the $250,000 prize is crowned in the Season 10 finale. The eliminated players also return to weigh in for the $100,000 at-home prize.