Journey to the rugged mountaintops of Montana and Canada to explore the imperiled whitebark pine as it edges toward extinction. As a keystone species, the stately five-needle pine provides shelter to dozens of high mountain creatures while its nutritious cones are packed with protein-rich seeds - a major food source for grizzly bears. But a deadly disease, beetle attacks and human-altered fire landscapes are rapidly turning these vital trees into ghost forests. Meet the scientists and land managers taking on the uphill challenge to save this iconic tree species.