The Alpaca Stones are a legend that few know about and even fewer believe. The people who do know have been killed, victims of Cassandra Prophet, who will do anything to make sure no one can solve the riddle of the stones. Doc and Marcus's vacation comes to an abrupt end when the stones are delivered to them at their hotel from a former client, who mysteriously disappears. The eighteen hand carved stone are a partial map, but of what? As the men try to piece together the puzzle, friend and bonded courier, Sydney Belleshota, is on her way to the desert town of Poison Springs to deliver a secret letter to a man she's never met. When he ends up dead, she becomes Prophet's next target. Her only means of escaping the town are with Doc and Marcus's help-but they've got problems of their own.