At Windover Bog in Florida, construction workers digging a pond uncovered a burial ground that turned into one of the most important archaeological finds in North America: over 160 skeletons up to 8,000 years old, preserved in peat so well that some skulls still held intact brain tissue. Forensic experts and archaeologists work through the evidence, extracting ancient DNA, examining woven textiles far older than anything expected from Stone Age hunter-gatherers, and using facial reconstruction to put faces back on people who died seven millennia ago. Much of what they find points to a settled, cooperative society that cared for its sick and buried its dead with ritual. But one skeleton complicates that picture: a man killed by a blow to the head and then decapitated, a act the film treats as a cold case to be worked with modern forensic tools. The result is a detailed look at what bog preservation can reveal about a culture with no written record and no name of its own choosing.