Professional kayakers Rush Sturges and Evan Garcia return to familiar grounds as they take on the raging rapids along the Columbia River Gorge. Approaching the river, they instantly feel the freezing temperatures of the water. The fast-flowing river leads to a 30-foot waterfall. Evan explains that he is recovering from a serious rib injury; so, even though he is joining Rush, he doesn't know if he will want to risk dropping over the waterfall. They start to paddle down the river, battling the treacherous water and dodging logs and rock hazards in the way. Before reaching the 30-foot waterfall drop, they stop to discuss Evan's chances of hitting it. He decides to go for it with no hesitation. Rush and Evan run the falls successfully and reflect on their excitement of being able to have this incredible scenery in their backyard. On Mt. Hood, cave explorers Eddy Cartaya and Barb Williams enter a glacier cave to perform research. Approaching the entrance they notice the drastic difference in size from previous visits. Due to warming temperatures, the cave is rapidly melting and falling apart, there are multiple cracks in the ceiling and huge chunks of ice on the ground. Eddy and Barb work quickly to avoid witnessing a potential collapse. They measure the cave and gather useful data as the walls of ice melt around them. After collecting as much research as they can, they escape the cave unharmed. Outside, they look back and wonder how much longer it will be intact, hoping they can continue to study it but realizing it may disappear much sooner than expected. In Crater Lake National Park, Bill Anders helps Jennifer Gifford maintain the hiking trails along one of the most spectacular natural wonders in the world, Crater Lake. To preserve the serenity of the wilderness around the lake, they use an old school crosscut saw to clear a log in the hiking trail, so hikers can continue to enjoy the beauty of this landscape.