The story picks up nine months after the season eight finale. Libero addresses viewers directly, explaining that Lele and Bianca have moved to Paris, Dante and Melina to Sulmona, and Anna is in London for her senior year at a private college. Libero and Enrica are no longer tending Nilde and Andrea Biglietti's Apulian farmhouse and have returned to permanent residence in Poggio Fiorito. On a plane to Rome, they meet Lorenzo Martini, son of Achille (one of Libero's Italian-American brothers), and Sara, sister of Marco Levi. Unaware that they share in-laws, the two find themselves living under the same roof. Lorenzo is a doctor who begins working at Villa Aurora after a brilliant career in the United States, and is hosted by his uncle Libero.
Maria and Marco are busy preparing for the wedding of his younger sister, Sara, who is arriving from America. Grandpa Libero and Enrica are also awaiting the arrival of Lorenzo, a surgeon and Libero's nephew.
Sara reveals to her brother Marco that she will no longer run competitively. By making up a lie, she covers up the truth: Sara, in fact, also suffers from heart problems. Meanwhile, her wedding gifts are sent back.
It's Elena and Bobò's first day of high school, and both are gripped by their first anxieties and fears. Elena decides to skip school and go to the beach with Tommy, whom she's immediately fallen in love with. Bobò will cover for her.
Giada's arrival at the Martini house is like a bolt from the blue. The only one she's spoken to for a while has been Sara, who wants to help in any way she can the girl she rescued on the street.
Sara begins managing the new bar across the street from Casa Martini. On the opening morning, however, a young manager from a chain of aperitif bars, Stefano, shows up and wants to take over the place.
Sara is robbed at the bar by two men blackmailing Giada. Lorenzo finds Sara unconscious on the floor and calls an ambulance. At the clinic, the young woman wakes up and learns from Lorenzo that she should have a CT scan.
Grandpa Libero and Grandma Enrica are busy getting Palù and Jonathan vaccinated at the clinic. Stefano takes Sara to his country estate, and the two become very close.
Lorenzo is running with Sara, who, overdoing it, ends up feeling ill, given her heart problems. Grandma Enrica and Ave convince Grandpa Libero to go on a diet and take an oriental gymnastics class.
After the night spent together, Lorenzo tells Sara that the situation is difficult and they can't be together. However, the two continue to grow closer, even when they decide to go to the movies separately.
Sara and Stefano spend a wonderful day paragliding. Everything turns dark when Sara reveals that, due to a heart defect, she could die at any moment.
A newspaper reports that Marco and a certain Fiamma, an athlete and acquaintance of Sara's, are having a romantic relationship. Maria discovers this, but her husband assures her it's just a journalistic invention. Could it be true?
Stefano and Sara spend the night together, but nothing happens between them. However, the young man makes a mistake and finds himself in the living room of the Martini family, with the entire family. He finally gets to meet them!
Marco and Maria discover the whereabouts of Giada's little brother, Daniel. His parents agree on one condition: Daniel must not know that Giada is his sister, nor that he was adopted.
Thanks to Maria's help, Giada manages to meet her brother, Daniel. They immediately connect, even though the little boy doesn't recognize his sister. Lorenzo, on the other hand, is very nervous about the operation he has to perform.
Lorenzo and Veronica continue to meet secretly at the hotel. Sara arrives, warning them that Fabio is coming. To avoid arousing suspicion, Sara kisses Lorenzo, and the two pretend to be engaged.
Sara and Stefano bring Marco home, but he doesn't remember anything and has even lost his wedding ring. So, his sister and her fiancé decide to investigate. Tommy paints a mural dedicated to Giada.
Fiamma is forced to reveal the truth, saying that nothing happened between her and Marco; he was drunk and kept repeating Maria's name. The two, therefore, make peace...for now.
Giada and Tommy decide to run away and escape from everyone. Maria and Marco, having discovered everything, decide to go look for them with the help of Lorenzo and Veronica.
Lorenzo takes his wife to the mountains, to the Majella, to spend time together. But during their vacation, Lorenzo is forced to reveal to Veronica about the night he spent with Sara.
Maria can't bring herself to tell Marco she's pregnant, but the situation becomes increasingly exasperating until she is forced to come clean.
Lorenzo remained in Poggiofiorito to care for his uncle, who faked a broken leg, hoping something would blossom between him and Sara. One night, however, the young man dreams of finding himself in a place with him.
Lorenzo and Sara have finally decided to force fate and get together. For this reason, the young man decides to leave for America and reveal everything to his wife.
Stefano takes Sara to the clinic, where Oscar tells her that her heart is failing and the only solution is to be admitted immediately for surgery. She decides not to tell Lorenzo.
Lorenzo decides to speak to Dr. Savino himself, but he hides behind a medical confidentiality pact. Oscar remains her last resort, and from him she manages to uncover the truth and the illness Sara is suffering from.
A little girl finds Sara unconscious on the beach. She calls Lorenzo on her cell phone, who rushes to her and, after resuscitating her, takes her to Villa Aurora.
While Grandpa Libero, Grandma Enrica, and Ave pray for Sara's recovery after the surgery, Lorenzo finds a television on which he can watch a video recorded by Sara before the operation.
Thanks to Maria's help, Giada manages to meet her brother Daniel. Between the two she is immediately understood, even if the little one fails to recognize her sister. Lorenzo, on the other hand, is very agitated about the operation he has to carry out.
Lorenzo and Veronica continue to meet secretly in the hotel. This is where Sara arrives, warning them that Fabio is on the way. In order not to arouse suspicion, Sara kisses Lorenzo and the two pretend to be engaged.
Sara and Stefano take Marco home, but the latter doesn't remember anything and has also lost his wedding ring. For this, her sister and her boyfriend decide to investigate. Tommy draws a mural dedicating it to Giada.
Fiamma is forced to reveal the truth, saying that nothing happened between her and Marco, he was drunk and kept repeating Maria's name. The two, therefore, make peace… for now.
Giada and Tommy decide to flee and get away from everyone. Maria and Marco, having discovered everything, decide to go and look for them with the help of Lorenzo and Veronica.
Lorenzo takes his wife to the mountains, on the Majella, to spend time together. But, during the vacation, Lorenzo will be forced to reveal to Veronica about the night spent with Sara.
Maria fails to tell Marco that she is pregnant, but the situation becomes more and more exasperating until the girl is forced to spill the beans.
Lorenzo remained in Poggiofiorito to assist his uncle, who faked a broken leg hoping that something would arise between him and Sara. One night, however, the young man dreams of being in a place and, with him.
Lorenzo and Sara have finally decided to force fate and get together. For this, the young man decides to leave for America and reveal everything to his wife.
Stefano takes Sara to the clinic and here Oscar tells her that her heart can no longer hold up and the only solution is to immediately go to hospital and undergo surgery. She decides not to say anything to Lorenzo.
Lorenzo decides to speak to Dr. Savino himself, but he is hiding behind professional secrecy. The last beach remains Oscar, from which he manages to discover the truth and the disease Sara suffers from.
A little girl finds Sara on the beach, unconscious. With the girl's cell phone, she calls Lorenzo, who immediately runs to her and, after reviving her, takes her to Villa Aurora.
While grandfather Libero, grandmother Enrica and Ave rely on prayers to ensure that Sara recovers after the operation, Lorenzo finds a television on which he can see a video recorded by the girl before the operation.