Watch The Biggest Loser Season 9 Episode 4 Online

This week starts off with a high-stakes pop challenge in which contestants race for the prize of immunity - and the winning team also gets three envelopes to give to the teams of their choice with instructions that could have a dramatic impact at this week's weigh in. Also, tensions are high between the trainers and one team suspected of game play, and a lifting competition rewards the winning team with a prize that everyone wants.