Italy, the late 1970s. While a mysterious and lethal "Black Fever" ravages the factories of Sesto San Giovanni, wealthy intellectual Corrado Mancini hosts an exclusive retreat at Il Belvedere, his private villa accessible only by boat. Amongst fine wine, political debate, and summer dancing, the elite feels safe behind their walls of privilege. But the illusion of safety shatters when a stranger appears in the grand salon.