For years, wildlife filmmaker Casey Anderson has tracked mountain lions by his home in Montana, but always from a distance. That all changes when he's invited by a Chilean filmmaker to join a film crew in Chile's Torres del Paine National Park, home to what may be the densest population of pumas on Earth. Follow his once-in-a-lifetime opportunity to get an up-close look at these normally reclusive creatures. See how, in this protected environment known as the Puma Triangle, these big cats behave in ways unlike anywhere else on the planet.