It is six years after Unification and Sicily is in chaos. Bandits rule the hills. Waves of cholera kill thousands. The Mafia begins its vicious reign of organized terror, raping a population squeezed by conscription, crippling taxes, and corrupt officials. At a high-class house near Palermo, three prostitutes have been knifed to death, their foreheads slashed with a strange mark, their bodies dumped on the madam's doorstep. When the chief inspector does nothing to solve the case, the madam summons her lifelong friend, Serafina, and asks her to catch the killer.