Elderly local woman Mari Baroja is poisoned, breathing her last at the Durant Home for Assisted Living. Sheriff Longmire wants to know who's been to see her lately. As the Sheriff enters the outermost edge of her web, he sets in motion a string of disturbing occurences involving members of the isolated community: the coal and methane industry, the former Sheriff, and other interests. With Deputy Victoria, Mr. Santiago, and his friend Henry Standing Bear, Longmire must wrangle a man with an appalling history of abuse.