Seven-time Everest summiter Pete Athans, and big wall climber Renan Ozturk take on the dangerous job of climbing into the crumbling caves. Their goals are to get inside the inaccessible cave cities that humans have not entered for hundreds, if not thousands, of years to document what's inside and to search for nine legendary cave temples called "kabum." What they find goes far beyond their expectations, rocking the Himalayan world and rewriting the history of this remote and mystical region, previously off-limits to outsiders.