Hurricane Harvey lashed North Padre Island National Seashore exposing tons of silver coins lost since three Spanish Galleons sank in 1554. News about the coins, located in a Park Service archaeological protection area, goes viral on internet treasure hunting sites. Swarms of treasure hunters, arriving by car, truck, and boat, leave the Park Service law enforcement team of Doug Fletcher and Rachel Randall struggling to enforce the treasure hunting ban on the nearly fifty miles of National Seashore.

During a morning beach patrol, the rangers discover a body buried in a shallow grave. A Spanish coin hidden in her wetsuit hints at a link to treasure hunters. Doug and Rachel both struggle to balance their home lives with the murder investigation.