Piemonte, Italy, 1769. Elisa Scalzi is a poor but beautiful and determined young lady, who pleasantly takes care of the old Countess Agnese Ristori of Rivombrosa. Anna Ristori, Agnese's daughter, is jealous of the privileged relationship Elisa has with the countess (who took her at her service as her lady companion although Elisa was only a maid). The Countess's health gets worse and she keeps expressing her desire to see her son, the charming Count Fabrizio Ristori, who has been enlisted in the French army for the past 10 years. Elisa decides to communicate the Countess' desire to see Fabrizio, so she writes him a letter and signs herself as "Elisa di Rivombrosa" . As soon as Fabrizio gets her letter, he decides to come back home. Before leaving, he's asked to deliver some important and confidential documents to a friend, Capitano Lombardi, who would be waiting for him on the way home. When the two friends meet, they're ambushed by a group of soldiers, sent by Duke Ottavio Ranieri, an evil and influent aristocrat and Commander of the Guard of his Majesty the King, who wants to steal these precious documents in order to save himself and several other plotting nobles from prison and death penalty.
Although Fabrizio manages to chase the killers away, Captain Lombardi is seriously injured. Just before dying, he hands Fabrizio the documents and asks him to personally deliver them to King Carlo Emanuele III.
Fabrizio then goes home to the beautiful Estate of Rivombrosa, where everyone is pleased to see him after so long. When he meets Elisa, he's amazed by her beauty. Not knowing she's a maidservant, he mistakes "Elisa di Rivombrosa" for an aristocrat because she's smart and well educated. He tries to seduce her, and Elisa realises she's seriously falling for him.
Fabrizio shocks everyone - his sister Anna and all the other nobles, well aware of the girl's un-aristocratic conditions - when he dares invite Elisa to dance with him at a ball in honour of his return. The ball is interrupted by Dr. Antonio Ceppi, a former noble man who lost all of his properties and his title after getting married with Lucia, a servant girl. He's seriously worried about his wife, who can't be found, and asks the nobles to help him. The Count, against everyone's will, decides to help Antonio to look for his wife. Lucia is found dead in the lake: she committed suicide because she felt responsible for her husband's social downfall and wanted him to be happy and accepted by the Upper class.
Her desperate action makes Elisa confess her social position to Fabrizio, who really gets mad at her. He starts to treat her roughly and rudely, trying several times to take advantage of her. He even ends up locking her in a cellar, in order to subdue her. When his mother is about to die, he releases Elisa. Countess Agnese Ristori, who really loves the young girl, asks her son to take care of her. After the death of the Countess, Elisa, still traumatized by Fabrizio's behaviour, decides to leave Rivombrosa and find a job somewhere else. The Count, however, doesn't want to give up on the girl and persuades all the aristocrats in the neighbourhood not to hire her. Because of this, Elisa decides to go back to the village, to live with her mother and sister. On the way home, she is attacked by the drunken Count Giulio Drago (Fabrizio's best friend). Elisa hits him with a stone and ends up in prison. When Fabrizio is informed of it, he first tries to convince his friend Giulio to remove the charges against Elisa. When his friend refuses to do so, Fabrizio goes to Turin to ask the king for Elisa's grace in exchange for the confidential documents.