A PHOENIX COLD CASE: David Mapstone has returned to Phoenix, Arizona, the desert city he left behind a lifetime ago. The ex-cop, ex-history professor is working the police dept's cold case desk, unearthing long-buried secrets. And he's good at it: as an ex-historian Mapstone knows the past is never past, as an ex-cop he knows he can't trust anybody... SOUTH PHOENIX RULES: Jax Delgado, a New York professor in Phoenix to research his next book has been tortured, murdered, his head severed and sent to his girlfriend. It shouldn't be an assignment for Mapstone, but the girlfriend in question just happens to his sister-in-law, Robin. Delgado's murder has all the hallmarks of drug cartel execution, and Mapstone fears Robin could be the next target. But is she as innocent as she claims? And why would a professor be targeted by a drug cartel? Mapstone's investigation will compel him to cross the line into South Phoenix, a world that plays by a different set of rules: South Phoenix Rules.