A nineteenth-century Italian noblewoman, imprisoned in a foreboding lakeside palazzo by her uncle, comes to believe she's possessed by a long ago mistress of the manor.

The film follows the struggles of an idealistic Catholic politician.

Franco, a young man of noble descent, marries Luisa, daughter of a humble clerk, against his grandmother's will.

The nobleman Franco Maironi is sailing over Lake Lugano together with his beloved Luisa. Luisa is from a bourgeois family and therefore marrying her would mean going outside his social class. But this is be no problem for the courageous young Italian patriot.

A nineteenth-century Italian noblewoman, imprisoned in a foreboding lakeside palazzo by her uncle, comes to believe she's possessed by a long ago mistress of the manor.

Franco, a young man of noble descent, marries Luisa, daughter of a humble clerk, against his grandmother's will.