Maggie Keller's PhD. is in jeopardy... Facing an anonymous accusation of plagiarism, a doctoral committee ready to expel her, and contradictory support from her academic advisor, Maggie plays a last-ditch wild-card that stalls their verdict on her dissertation, attracting the attention of Katherine Sapp, a mysterious government agent. Katherine and Tony, her Homeland Security partner, offer Maggie a deal: they will validate the graduate student's research on lost Viking-American colonies in exchange for helping them solve their investigation into an Ozark treasure mystery - the Madre Vena Ore Cache. But in doing so, Maggie must locate her estranged sister, Dutch, who may be involved in a related string of illegal cave intrusions and grave robberies with a rival Australian treasure hunter named Hawk. When the joint expedition finds the legendary cave, both siblings are reunited over the discovery of a mysterious Viking sword. But with no sign of the fabled treasure in sight, Katherine ...