As the chill of autumn sweeps through the countryside, Tamarack County sheriff Cork O'Connor is about to face a season of murder, adultery, and deceit that will take him from seedy backwoods bars and humble reservation shanties to the highest and most corrupt echelons of Chicago society. Lured to the nearby Ojibwe reservation on what appears to be a routine call, Cork finds himself the target of a sniper's deadly fire. Then, a mutilated body is found perched above the raging waters of Mercy Falls. The victim is Eddie Jacoby, a Chicago businessman involved in negotiating an unpopular contract between his management firm and the local Indian casino. Sparks fly when the wealthy Jacoby family insists on hiring Dina Willner, a beautiful private investigator, to consult on the case, and when Cork discovers a tie between one of the Jacoby sons and his own wife, Jo.