The film opens with a young woman tearfully leaving her son to live with his grandmother. She promises to come back for her boy. Several years later, in 1753, in Venice, Casanova, is notorious for his success and promiscuity with women, his adventures being represented in puppet theatres around the city. The Doge, the ruler of the city, is sympathetic to Casanova, but cannot be too lenient to avoid trouble with the church. He warns Casanova that he must soon marry or he will be exiled from the city.
Casanova is in love with Francesca, who writes illegal feminist books under the name of a man, Bernardo Guardi, and argues for women's rights as Dr. Giordano de Padua. However, her mother pushes her to marry Paprizzio, a rich man from Genoa whom she has never seen. When Paprizzio arrives in Venice, Casanova lies to him and says that the hotel he booked is closed and he persuades him to stay at his house. Casanova also lies and says that his nom de plume is Bernardo Guardi. While Paprizzio, preparing to visit Francesca, stays at Casanova's house, Casanova visits Francesca, pretending to be Paprizzio.
During the Venetian Carnival, Casanova confesses his true identity to Francesca, which makes her angry. Casanova is arrested by the Venetian Inquisition for crimes against sexual morality, such as debauchery and heresy with a novice. However, he saves Francesca by pretending to be Bernardo Guardi, which impresses her very much. At his trial, Francesca reveals that it is in fact she who is Bernardo Guardi, and both are sentenced to death. Just as Casanova and Francesca are about to be hanged in the Piazza San Marco, they are saved by an announcement that the Pope gave amnesty to all prisoners who were to be executed on that day, as it was the Pope's birthday. It is later discovered that the "Cardinal" who gave the announcement was actually an impostor who happens to be Casanova's stepfather, wedded to his long-lost mother who came back for him just as she promised when Casanova was a child. As they all escape on Paprizzio's boat, Francesca's brother, Giovanni, stays behind to continue Casanova's legendary womanizing.
* Well, who doesn't fall in love with the handsome, sweet talking Casanova? He was a playboy, and we all know playboy won't soo easily, properly and trully fall in love with a women. But he did fall in love, but not into those 'liltle girl waiting to get married' type women. The women he fell in love is the one who can stand up on her own, and say whatever she feels is correct or should be, and she doesn't care how high profile you are, she'll be just herself, she won't wear any 'mask' to protect herself. And I guess Casanova really find her different from other women, thus he doesn't care to lie, to impose and to pretend someone he's not, to protect the women he love. For all those stupid things (well, I think womanizing is not good lah) he'd done, he is after all, a guy who still manage to behave himself properly!