A partially true story about lies told, virtue lost and love found.
In 1753, in Venice, Casanova, portrayed by the late Heath Ledger, is notorious for his success and promiscuity with women, his adventures being represented in puppet theaters 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 right as Dr Giordano de Padua. However, her mother pushes her to marry Paprizzio, a corpulent 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.