The competition heats up when the players learn that whoever loses 2% of their body weight first this week gets immunity. The catch is that only one person gets immunity and they only get one shot to weigh in whenever they think they?ve reached that goal. Later, the players head to the pool for a swimming challenge involving weights. After each contestant finishes the race, they are allowed to go back and help others finish, which proves very revealing about who the players want to stay in the game -- and who they don?t. Alison Sweeney hosts the series, and trainers Bob Harper and Jillian Michaels also star.