Growing up in rural West Virginia, Tommy hears dark Appalachian lore from his grandmother—most notably the legend of the "Devil’s Mud Man," a malevolent entity born from cursed earth that preys on the isolated.
Decades after his grandmother recalls finding a murdered woman tied down in Apple Creek as a child, new female bodies are discovered submerged in nearby waters, prompting Tommy to suspect his eccentric veteran friend, Old Wesley. Upon breaking into Wesley's trailer, Tommy finds no evidence of murder, but instead a lonely, traumatized man haunted by his own terrifying encounter with a shadowy figure near the creek. The true killer is eventually revealed to be their neighbor, Farmer Ronny, whose barn hides a fresh victim and whose property contains several shallow graves; however, Ronny claims he was driven to commit the acts by an ancient, corrupting voice emanating from the land itself.
Even after Ronny's arrest and life sentence, Tommy and his grandmother remain convinced that the serial murders were merely the work of a supernatural entity using weak men as its host, leaving an enduring fear of the dark woods passed down through generations.