The action takes place in Aldrovandi castle in the Mugello region in the early 17th century, at the time when Ferdinando I de’ Medici was the Grand Duke of Tuscany.
Legend has it that when the first snow of the year falls, a ghost appears in Aldrovandi castle. She is the wife of an old count, who killed her when he caught her with a lover. It is said that the spectre has decided to avenge herself by killing young members of the Aldrovandi family who have recently fallen in love. She is thought to have taken two lives so far.
When the first snow of the year falls, the current count fears for his daughter Vanna, who is young and in love. He wants to know who has won her heart but she refuses to say. Therefore, the count asks for help from Gualberto Vismundi, who turns up dressed as a jester at a party the count is holding to dispel fears about the curse. The count asks him to find out who his daughter’s lover is and kill him, hoping that this will mean that Vanna will not be the one who dies. The count does not know that Gualberto himself was once Vanna’s lover.
Vanna welcomes her sweetheart Gilfredo, but he has to flee when the count and Gualberto arrive. The latter tries in vain to follow Gilberto. Next, Vanna and Gualberto quarrel. When he sees that he has no chance of winning her back, Gualberto threatens to tell Vanna’s father about their former relationship. Absolutely terrified, Vanna shoots Gualberto and kills him. A little earlier, Gualberto had struck a fir tree with an axe in an act of bravado associated with another legend. It was said that whoever started chopping down the tree would be buried in a coffin made from its wood. Vanna tries to call Gilberto, but she finds out that he has been killed and she drops dead herself just as some peasants finish felling the fir tree.