At the tail end of 1967, the Parker family once again finds it impossible to hide from a world spinning out of control. Fourteen-year-old Top still can't fit in with their Center Springs, Texas, community, and his near-twin cousin Pepper does the only thing she can conceive to escape her own demons: she joins the Flower Children flocking to California—just as three businessmen are murdered in the Red River bottoms on the same night as a deadly hit and run.

Constable Ned Parker wonders if these crimes are connected, but when Pepper disappears, he follows, leaving the investigation in the hands of Sheriff Cody Parker, who hires Deputy Anna Sloan, an investigator with an eye for detail. Following her instincts, she trails killers through a world nearly forgotten, the hunt's backdrop one of continuous rain, gloomy skies, and floods. When an ambush nearly kills her, the investigation accelerates into gunfire, chases, and hair-raising suspense, while out on Route 66 to California, a man named Crow isn't what he seems.

Lies, deception, and a band of outlaw motorcyclists prove to the Parkers that no matter where you turn, no matter what you do, the world is full of such darkness that even grandmothers are capable of unspeakable deeds.