As agent and scout for famed detective Allan Pinkerton's Secret Service in the first eighteen months of the American Civil War, Harry Raines has repeatedly risked his own life and experienced unbelievable horrors. Sick of it, he resigns from the service and retires to the horse farm he inherited from his mother in the upper Potomac Valley near Shepherdstown, Virginia. The idyll is quickly interrupted, however, when the local Presbyterian minister, a family friend, is found shot and hanged in lynch mob fashion,