Italy. Fin de siecle. A great Alpine house. Lorenzo returns from Paris with a strange diagnosis: syphilis contracted from debauchery. But he is not dissolute and it appears that his father too could not have infected him. His mother had raised him at a distance, educating him through numerous and endless letters about her life and about her husband's health. Lies, evidently. Sick, in his hands the evidence of a hidden, paternal vice, Lorenzo returns to the Alps seeking for  justice. Attempting to lead his mother - benevolently at first, then desperately,fiercely -  to a belated confession. That will not be obtained. To precede the most terrible and cathartic, conviction.