In Venice, during the spring of 1866, it is the last month of the Austrian occupation of the Veneto. The Italian government has forged a pact with Prussia, and another war of liberation in the ongoing Risorgimento is imminent. Countess Livia Serpieri, unloved by her collaborator-husband but sympathetic to the cause of freedom espoused by her patriotic cousin Roberto, meets Austrian officer Franz Mahler as she begs him to call off a duel with Roberto....