Scott Wolter receives a tip that there are pyramids at the bottom of a lake in Lake Mills, Wisconsin. As he investigates, he learns local legend suggests they were built by Aztecs and over time, they've been buried as land and water have shifted. Could the Aztecs really have a connection to the American Midwest? Scott dives into the mystery, quite literally–taking a personal submarine called a Fugusub down to the depths of Lake Mills to investigate the underwater pyramids. His quest then leads him to other sites in the Midwest including the pyramids in nearby Aztalan State Park. Could it be more than coincidence that the park shares the same name as the legendary ancestral home of the Aztecs? In the end, the key to proving whether there's truth in the legend of Aztecs in America could be in the discovery of shared practices, symbols and language between north and south of the U.S. border.