It is 1860; Garibaldi and his Thousand land in Marsala and turn Sicily upside-down. The aristocracy feels the closeness of the collapse of its own system, while a new class of opportunists, the wheeler-dealer bourgeoisie, gets ready to take advantage of the transformations in progress to try a bold political and business climb.
Don Fabrizio Corbera, prince of Salina, known as the Leopard, because of the rampant effigy in the family coat of arms, witnesses the events without taking part in them. He is, in fact, aware that his social class and his world are, now, agonising. Nor is he willing to trust the new prospects, which appear to him as not particularly alluring and illusory.
Hence, he approves of and encourages his favourite nephew Tancredi Falconeri, a resourceful and daring young man, to join the fight, first on Garibaldi's side and then with the more moderate Savoy dynasty, in order to control and pilot an inevitable change, trying to neutralise this process, to make it harmless and, in short, to leave everything as it was before. A strategy that is synthesised in the cynical imperative "everything must change if we want it to stay the same".
Don Fabrizio also advises Tancredi, who belongs to a distinguished family but with financial difficulties, to marry the beautiful Angelica, the daughter of Calogero Sedara, an newly rich farmer and post-union mayor of Donnafugata, a remote village where the Salina family own a big but decaying mansion. Angelica's exuberance and charm, together with the wealth of her dowry, will allow Tancredi to start on a brilliant political career. Don Fabrizio, on the other hand, refuses with bitter disenchantment the appointment as senator of the reign offered him by Chevalley, the government's envoy, suggesting in his place, not without a touch of mocking but gloomy irony, the ambitious Sedara.
Tired and disillusioned, the old Leopard entrusts only the unfathomable firmament with his nihilism and during a dance in honour of Angelica and Tancredi he feels the mysterious call of death approaching ineluctable. It is the lineage of the Salinas itself that draws towards its inevitable extinction.