Forensic geologist Scott Wolter sets out to test a fringe claim: that Norse explorers pushed far beyond the Canadian coast documented in the sagas and reached the interior of what is now the United States. He examines the Heavener Runestone in Oklahoma, reading its carved characters against known runic alphabets and weighing whether they are genuinely medieval or a later hoax. The trail also leads to an island off Massachusetts still littered with unexploded ordnance from military testing, where Wolter has to work around the danger to study stone markings and geological weathering patterns he argues support a Norse presence centuries before Columbus. The film moves between these sites, laying out the physical evidence piece by piece, from rune shapes to rock erosion, rather than simply asserting a conclusion. It treats the Vinland sagas as a starting point for a physical investigation rather than settled history, and leaves the viewer to judge how far the artifact trail actually stretches into the continent.