Dave Robicheaux and his ex-partner in Homicide, Clete Purcel, head for the mountains and trout streams of Montana for some much-needed healing. However, while Montana might seem an unspoilt paradise peopled by men and women from an earlier, more innocent time in American history, Dave and Clete soon find that there are plenty of serpents in the garden too. The deaths of a couple of hikers suggest a perverted serial killer may be at work, while an escaped jailbird and his former tormentor are locked in a savage dance of revenge that is ultimately connected to the fortunes of a wealthy oil family hiding a terrible secret.