When Detective Dave Robicheaux discovers disturbing secrets from his mother's past, he embarks on a journey through a murky world of vice, politics and murder. Robicheaux has been told that his mother, Mae, was a hooker and ended her life drowned in a mud puddle by two cops working for the Mob. As Robichaeux and his partner hunt for the killers, they hook up with a door-to-door salesman turned state governor, a psychotic hit-man, and the owner of the mansion at Purple Cane Road - who knows rather too much about Robichaeux's wife .