By 1886, the thundering herds were gone, leaving only silence across the Montana badlands. To save the American bison from total oblivion, the Smithsonian ordered a mission with a cruel, necessary irony: hunt down the last survivors to preserve them for science. You see, if the museum didn’t claim them, the coyotes or careless poachers would. This is the fascinating, slightly heartbreaking account of that final expedition, featuring a golden calf named Sandy and a team racing to immortalize a species before the sun set on the frontier forever.