A body falls off a train during a heavy downpour near Tucson, Arizona in late January of 1895. As the rain ends, the wagons of a traveling medicine show arrive in town with performers to entertain and a doctor of questionable credentials to peddle his wares.
Pima Gallagher, a detective for the Southern Pacific Railroad, assisted, or at least she thinks so, by Scout Walker, his eleven-year-old stepdaughter, try to learn the identity of the corpse and whether its sudden appearance has anything to do with the nearly simultaneous arrival of Dr. Blenheim's show. Meanwhile, Pima's brother and sister, back in his home state of Mississippi, are causing him a great deal of concern with their letters about brother Jefferson's deteriorating health.
Eventually things come to a satisfactory conclusion, but not before more murder and mayhem manage to put Pima and Scout in fear for their lives in the mountains and desert areas between Tucson and Phoenix.