For 50 years, many people have fought to protect San Bruno Mountain, a rare fragment of wild San Francisco and the largest undeveloped urban area in the country. Two men have spent most of their lives working to protect the mountain, in very different ways. The battle for this mountain led to a significant change to the Endangered Species Act and turned allies into enemies. This story is emblematic of a common divide within the conservation community. Directed by Ann Dunsky. Written and produced by Steve Dunsky.