In June of 1889 in San Francisco, John Muir, iconic environmentalist, writer, and philosopher, meets face-to-face for the first time with his longtime editor Robert Underwood Johnson, an elegant and influential figure at The Century magazine. Before long, the pair, opposites in many ways, decide to venture to Yosemite Valley, the magnificent site where twenty years earlier, Muir experienced a personal and spiritual awakening that would set the course of the rest of his life. Upon their arrival the men are confronted with a shocking vision, as predatory mining, tourism, and logging industries have plundered and defaced "the grandest of all the special temples of Nature." While Muir is consumed by grief, Johnson, a champion of society's most pressing debates via the pages of the nation's most prestigious magazine, decides that he and Muir must fight back. The pact they form marks a watershed moment, leading to the creation of Yosemite National Park, and launching an environmental battle that captivates the nation and ushers in the beginning of the American environmental movement