Los Angeles County sheriff’s deputy Charlie Hood is attached to the ATF, working undercover on the Iron River that flows across the U.S.-Mexican border. The diamond fillings he wears in his left canine glimmer, distracting the men who sell the illegal firearms that enable the unspeakable violence on both sides of the map. Spotting the sparkle when “Charlie Diamonds” opens his mouth is often their first step toward life behind bars.

Meanwhile, Bradley Jones, sheriff’s deputy and employee of the Baja Cartel and son of the love of Charlie’s life, the deceased L.A. outlaw Suzanne Jones, is expecting a son of his own. Suzanne was descended from famed Mexican desperado Joaquin Murrieta, whose embalmed head Bradley inherited from her and keeps nestled among piles of cash, proceeds from Bradley’s own life of crime.

Charlie knows all of Bradley’s secrets; the question is what will he do with the information. Until he decides, his obsession remains the inexplicable existence of Mike Finnegan, the diminutive devil who flits in and out of both men’s lives, knowing things he shouldn’t, seemingly immortal.

Three men - earnest law enforcer, inveterate lawbreaker, and the man who pits them against each other - hurtle toward one another in the jaw-dropping conclusion to T. Jefferson Parker’s mesmerizing vision of the border. Their climactic showdown brings to a spectacular close a crime series that obliterated the boundaries of the genre.