In Baja, Mexico, Gary and Bill point Ruby to a valley so remote that it has no name and has never been entered by a vehicle before. To get there, the trio has to cross the treacherously unpredictable Rio Hardy. Too deep to ford, their only hope is to partially sink Ruby and pray she can go the distance. They must cross the scorching mud trap that is the million-acre Laguna Salada salt plain to get to the valley entrance. But their way in is barred by a 35-metre high rock wall. Can Ruby scale it?