Six months have passed since a faded, black ledger mysteriously appeared on FBI Agent Jake Radley's doorstep. Puzzling over the document's sinister entries, Jake pieces together a story of mass murder near the Texas-Mexico border two decades before. If Jake's theory is correct, the names listed on the ledger's final page are the victims of a previously unknown serial killer. Leads are scarce until a gruesome new crime scene, deep in the Mexican desert, shows a chilling connection to the border deaths of long ago.