An archaeologist spying on the midnight rites of a cult group inside an extinct New Mexico volcano is murdered -- felled by the brutal thrust of a prehistoric spear-throwing weapon called an atl-atl. All the evidence points to one of Sheriff Charles Matthews's own deputies, Raul Trujillo, as the killer. But Matthews doesn't buy it. And to prove his deputy's innocence, Matthews will take off his badge and step into a haunted southwestern landscape where vengeance is still a reason to kill.