Angela Russo, a sixteen-year-old girl, is found dead in a river, having been fatally violated with a large blunt instrument. Inspector Di Salvo is assigned to the case and focuses his investigations on St. Theresa's, the exclusive school where Angela boarded. Three of the murdered girl's classmates, Franca, Paola and Virginia (who call themselves "The Inseparables"), receive threatening poems from an individual using the name "Nemesis." Bizarre "accidents" start to befall the girls: Franca i...