The Summit | 9:30pm | CBS

As the trekkers hit the halfway mark on their journey and venture toward the snow line, a divide in pace emerges within the group. After a daunting rappelling obstacle down a 500-foot vertical rock face, the group learns that they have broken a fundamental rule of THE SUMMIT – that the group must travel together at all times – and having ignored the Mountain’s Keeper’s repeated warnings, must endure the game-changing consequences.