When the mysterious appearance of an endangered snake leads to murder, special agent Sam Rivers must solve the case before those responsible can slither away.

The appearance of a rattlesnake wouldn't normally be enough to halt construction on Alta Vista, an upscale housing development in Southeast Minnesota's bluff country. But this is no ordinary reptile; it's a rare eastern massasauga rattlesnake (EMR). The endangered snake has not been seen in the region for more than two decades, so Sam Rivers is called in. As a special agent of the US Fish and Wildlife Service, Sam takes his responsibilities seriously-especially when it comes to protecting endangered species and their habitats. If he finds EMR dens on the construction site, he'll close it permanently.

While the developers protest in outrage, Sam enlists the help of herpetologist Gina Larkspur from the Department of Natural Resources. Together, they begin to find anomalies that call the entire situation into question. When Sam's wolfdog, Gray, tries to sniff out the EMR dens, it isn't rattlesnakes he finds. Instead, Gray discovers the remnants of a terrible, 25-year-old crime. Were the endangered species merely pawns in a diabolical coverup? As Sam searches for the truth, bodies begin to pile up. He and his team must race to find answers before more innocents die.

Natural history writer Cary J. Griffith brings back Sam Rivers for his fifth outdoors-themed mystery-a suspenseful novel filled with fast-paced action.