Season 3 picks up with Elena and Lila, both now grown women, during the great open sea of the 1970s. Lila took her young son and left her husband and a comfortable life to work as a factory worker in the toughest of conditions, while Elena left the neighborhood to study in Pisa, and is now an author of a successful novel that has paved the way to an affluent and cultivated world. They now navigate a scenario of hopes and uncertainties, still united by their strong and ambivalent bond.
After Nino's unexpected appearance at her book presentation in Milan, Elena realizes her childhood crush never really abandoned her, and doubts begin to form about her fiance Pietro. Later, a scathing review leaves Elena questioning herself as a writer.
A nervous Elena introduces Pietro to her family, and, though he instantly charms his future in-laws, Immacolata rejects their plans for a civil wedding ceremony. Months later, Lila falls ill due to the deplorable conditions at the Soccavo factory and makes Elena promise to take care of her son Gennaro if anything happens to her.
Concerned about Lila's worsening health, Elena seeks advice from her future mother-in-law Adele, who encourages her to write an expose on the Soccavo plant and the mounting unrest between rival unions. After several doctors' visits, Lila becomes determined to move back to the neighborhood despite being viewed as a pariah.
After a tense argument about plans for a family, Elena and Pietro marry in town hall, and later, are surprised with a reception organized by Adele. Though she had hoped to concentrate on her next book, Elena gives birth to a daughter and struggles to find time to write.
Following news of a murder in Naples, Pasquale and Nadia turn up unannounced at Elena's house in Florence, further fuelling discord with her husband. Meanwhile, Elena suspects all is not right with Lila when she's asked to take Gennaro on their summer beach trip.
On holiday, Elena grows increasingly exasperated with Gennaro and after receiving shocking news about her sister Elisa, she cuts the family trip short to travel back to Naples. Later, tensions mount at a dinner with the Solaras, and Pietro shares his unvarnished opinion of Lila with Elena.
Elena's marriage is more and more in crisis, Pietro is distant and she feels treated like a servant. One day, Nino Sarratore shows up at the Airota's door. He and Pietro become friends and say goodbye with the promise to meet again. Elena anxiously awaits their next meeting and finally resumes writing.
Elena and Pietro meet Nino's family. Nino gives Elena his feedback on the manuscript, when he discovers that Pietro has not read it he shows hostility towards her, but in a veiled and underhanded way. Pietro's reaction to Nino's passive-aggressive attacks only confirms Elena's doubts about her husband.