Mark Cornelison

"The Biggest Loser" returns with a bang for season 13 when the contestants arrive at the ranch and get one of the biggest surprises ever in the series' history. They arrive in teams of two -- including mother/daughter, father/son, brother/sister and husband/wife, all eager to change their lives together. But they're shocked to discover that they will not only be split up -- they will also be competing against the person they came with. They'll be pushed out of their comfort zones in a way they have never been before -- and one team won't even make it on to the ranch -- as the season of "No Excuses" begins. The players all have different excuses for why they never lost weight before. So the season of "no partners" will also be a season of "no excuses" -- as week in and week out, all the typical reasons for not getting in shape will be addressed. Alison Sweeney hosts the series, and trainers Bob Harper and Dolvett Quince also star.

This week, a surprising turn of events shakes up the competition, and the contestants compete in a rough and wild short version of a “Tough Mudder” competition. But they won’t be doing it alone - with them will be the show’s three most recent winners John Rhode, Olivia Ward and Patrick House. Host Alison Sweeney helps motivate the remaining contestants by telling them the player with the highest percentage of weight loss at the weigh-in will win a Ford Escape SUV. Later, the players stroll down memory lane with the trainers and watch video journeys of how far they’ve really come from their first day on the ranch before an emotional weigh-in determines which player will walk away with a brand new car.

This week kicks off with a Chinese buffet temptation that will give the winner complete control of how contestants will be matched up for a face-off challenge in the gym -- and also give them a two-pound advantage to use or give away. Later, trainers Bob Harper and Dolvett Quince coach the contestants through a wild water-transfer challenge that will reward the winning team with the most coveted prize of all -- video chats home. And one player makes a shocking decision that stuns everyone before another contestant is sent packing following the weigh-in. Alison Sweeney hosts the series.

The stakes are high this week as the red and black teams compete in a fierce battering ram challenge that will give one team exclusive rights to the gym, while the losing team has to find other creative ways to burn calories. Both trainers - Bob Harper and Dolvett Quince - struggle with certain contestants who they feel aren't giving it their all, making it tougher for both teams to get the weigh-in win each one wants. Alison Sweeney hosts the series.

In this season of "no excuses," this week's challenge addresses the excuse "I can't lose weight on my own." Trainers Bob Harper and Dolvett Quince are suspended over water in a wild dunk tank-like challenge in which the red and black teams have to use their strength to keep a weight from landing their trainer in the pool. The losing team has to do without their trainer all week until the last chance workout. Once the losing team is determined, one contestant admirably steps up to lead their group while their trainer is away, with none of them aware that he is secretly watching how they do in his absence. Later, a very heated elimination sends another player home after a tense weigh-in to see how both teams did this week.