Bill, Gary and Ruby now take on the Sierra Juarez mountains in southern Mexico, a staggering 1,800 metres above sea level. Following a Native American foot route to a sacred rock platform, our heroes are greeted by a maze of granite boulders that threatens to topple, wedge, or crush them at every turn. Later, lost in the dense mountain forest, Gary scales a 20-metre pine tree using Ruby's winch as a tree elevator to scout a way out. Finally, the guys get to the base of the sky platform, but the 500-metre high natural rock staircase leading up to it could prove to be a challenge too far.