McPhee recounts a journey that he made with conservationist David Bower, geologist Charles Park, and two medical students, Larry Snow and Lance Brigham, through the Glacier Peak Wilderness in the Cascade Range in Washington State. They hiked to a remote cabin, used in winter by the Chelan County Snow Survey to measure snow depths crucial for predicting water runoff. The cabin, stark and peculiar in the summer forest, serves as a haven for McPhee and his companions.

The hike reveals the beauty of the Cascades, which some consider the most beautiful mountains in the US or even the world. This wilderness area was preserved by the 1964 Wilderness Act, but an exception allows for mining claims. At the heart of their journey is a copper lode owned by the Kennecott Copper Corporation. The conversation between the men reveals the ongoing tension between conservation and resource extraction.

McPhee contrasts the perspectives of Brower and Park. Brower, a leading conservationist and former executive director of the Sierra Club, a prominent environmental organization, sees the wilderness as sacred and laments any intrusion by mining. Bower has spent his life advocating for the protection of such landscapes. In contrast, Park, a practical geologist and mineral engineer, views resource extraction as necessary and believes it can coexist with nature.