Bristol Bay produces nearly half the world's wild sockeye salmon, and beneath its headwaters sits one of the largest untapped copper and gold deposits on earth. FRONTLINE lays out the fight over the proposed Pebble Mine, talking to fishermen who have worked the bay for generations, Alaska Native communities who depend on the salmon runs for subsistence, and mining executives who argue the state needs the jobs and mineral wealth. Engineers and geologists debate whether tailings dams built to hold back mine waste can really be trusted to survive earthquakes and heavy rain in a region prone to both, while EPA scientists explain the risk assessment that led federal regulators toward blocking the project. The film moves between the boardrooms making the economic case and the boats and canneries where the salmon economy actually runs, tracing how a fight over one mine became a referendum on how much risk a functioning ecosystem can absorb. Originally aired in 2012, the film gains a coda from the EPA's 2023 determination, closing out a debate that ran for over a decade.