Rudy, Jen and Jacob journey to the Serpent Mounds, an ancient and sacred burial site on the north shore of Rice Lake. Dr. Rudy sends Jen and Jacob out on the lake to core for clues.  Chief Laurie Carr welcomes the team and shares knowledge about past excavations and the Hiawatha Nation’s fight for repatriation of the ancestors and their sacred artifacts. Back at the lab, the team helps Tynan Pringle analyse the lakebed sediment with cutting edge XRF technology to help unravel the mystery of how and when the mounds were built.