Siena, one of Italy's most beautiful cities, is feverishly preparing for the Palio, a horse race dating back to the Middle Ages, held every summer in the centre of the town. Tempers flare, rivalries between the competing neighbourhoods intensify. Milanese lawyer Enzo Maggione and his wife Valeria are unwittingly caught up in the death of a jockey and a maelstrom of plots, counterplots and bribes surrounding the race. What begins as a listless excursion to a medieval equestrian competition turns into a hallucinatory nightmare for Maggione and his wife, awakening their dormant libido, for each other but, more dangerously, for others in their entourage.