La desaparición de su vieja amiga, Lila Cerrullo, hace que la autora Elena Greco, de 60 años, reflexione sobre los primeros días de su amistad en Nápoles en la década de 1950, cuando Elena y Lila son dos chicas muy diferentes en lo más alto de su clase. Cuando las chicas descubren la guarida de Don Achille, una figura criminal que controla el vecindario, deciden confrontarlo.

Cuando el cuarto grado llega a su fin, Elena y Lila luchan con sus familias por la oportunidad de continuar su educación. Más tarde, un viaje fuera de la ciudad se convierte en un día que Elena nunca olvidará, y una muerte cambia las cosas en el vecindario para siempre.

Ahora, una adolescente, Elena se enfrenta a la pubertad, sus estudios y su amistad con Lila, que ahora trabaja en la tienda de reparación de zapatos de su familia. Después de que una ceremonia de entrega de premios de la biblioteca revela lo que Lila ha estado manteniendo en secreto, Elena se entera de cuáles podrían ser los grandes planes de su amiga. Lila toma una posición en contra de los peligrosos hermanos Solara.

Al ingresar a la escuela secundaria, Elena jura mantenerse por delante de Lila, académica y románticamente. Lila evita un desfile de pretendientes que compiten por su afecto, eligiendo en cambio centrarse en sus ambiciones en la zapatería. Al prometer un mejor futuro para el vecindario, Stefano Carracci invita a Elena, Lila y sus familias a pasar la víspera de Año Nuevo, pero las cosas toman un giro oscuro.

Elena se cansa de Gino, mientras que Lila rechaza a dos pretendientes potenciales a un costo. Una salida rara en la ciudad se vuelve violenta. Elena se preocupa por no estar allí para Lila después de aceptar una invitación para pasar el verano lejos del vecindario y su familia.

En la isla de Ischia, Elena se encuentra con la familia Sarratore, reavivando su enamoramiento de la infancia con Nino, quien está reñido con su padre, el encantador Donato. De vuelta en Nápoles, la resistencia de Lila al cortejo apremiante de Marcello llega a un punto de ruptura. En el día del cumpleaños número 15 de Elena, un encuentro inesperado la deja conmocionada.

Elena regresa a Nápoles para encontrar que Lila ha hecho una conexión romántica con Stefano, a pesar de la presencia inminente de Marcello. Mientras Lila adopta una vida más glamorosa al lado de Stefano, Elena le advierte sobre lo que la gente está diciendo en el vecindario. Más tarde, con la esperanza de mantenerse al día con su amiga, Elena anima a un pretendiente y rechaza los avances de otro.

Con las ventas de zapatos Cerullo a la zaga, Stefano corta un acuerdo comercial con las Solaras contra los deseos de Lila. Después de que Elena es expulsada de una clase por expresar su opinión, Nino la alienta a escribir un artículo para su revista sobre su experiencia. Más tarde, Elena y Lila se llevan sorpresas desagradables. Final de temporada uno.

With Lila on her honeymoon on the Amalfi Coast, Elena struggles to handle school and her relationship with Antonio. When Lila returns with visible bruises on her body, the two girls revert to their natural closeness and Lila’s will to take revenge against her husband grows. Elena continues to be bewitched by Nino Sarratore’s charisma but chooses not to mention him to Lila.

Elena's relationship is threatened when Antonio discovers she has asked the Solaras' help to keep him from doing military service, while Lila remains rebellious in her marriage to the often-violent Stefano. After a photo of her is exhibited at a wedding dress shop in the center of town and becomes the subject of much gossip, Lila makes a bet with Elena about how the whole affair will end.

Upset that her picture is featured prominently in the new shoe shop Stefano is opening with the Solaras, Lila comes up with a creative solution to deal with the matter and enlists Elena’s help. Though Lila begins working at the Caraccis’ new grocery store, she continues to resent her husband’s business activities and the source of their income. Model student Elena invites Lila to a party at her teacher Ms. Galiani’s house; there, the two girls become acutely aware of the fact that they belong to ever more distant worlds.

At Rino and Pinuccia’s wedding, Elena accepts Lila’s invitation to go on holiday, provided the destination is Ischia, where she knows she’ll find Nino. On the island, Elena, Lila and Pinuccia begin to spend more and more time with Nino and his friend Bruno and Lila starts to take a strong interest in Elena’s summer reads. As Lila and Pinuccia exhibit signs of nervousness when their respective husbands come to visit for the weekend, Elena is thrown when Lila comes to her bedroom to make a confession.

As Pinuccia returns to Naples, a new secret excites Lila and numbs Elena, who nonetheless becomes embroiled in its coverup. Subdued by Lila's charisma and indifferent to Bruno's flattery, Elena finds herself the keeper of a far darker clandestine series of events involving Donato Sarratore. After the girls encounter Michele and Gigliola, who have come to Ischia on a day trip, Lila seizes the opportunity to throw the whole truth in Stefano's face.

Following her formative summer on Ischia, Elena throws herself into her studies and looks towards a future outside of the neighborhood. After a brilliant finals performance, Elena happens upon Lila, who is working at the shoe store and has grand plans for a fresh start. As Elena leaves Naples to commence her prestigious university studies in Pisa, Lila decides to leave Stefano and moves into a modest apartment, but the failings of her plan soon emerge.

Three years into her time in Pisa, Elena has developed into an elegant and cultured young woman – but still feels like an outsider. After a consequential breakup, Elena falls ill and is visited by her mother, who has come to nurse her back to health. During the night, Elena takes to reading Lila’s diaries, which were entrusted to her for safekeeping; in these tomes, Elena discovers Lila’s dedication to her new role in the face of Stefano’s increasingly violent behavior.

With graduation in sight, Elena is overwhelmed by memories of her past and copes by drafting her first novel. Meanwhile, she finds a new suitor in Pietro Airota, the son of an esteemed academic. After Pietro proposes, Elena entrusts him with her manuscript before heading back to Naples, where she reunites with her family and visits Ada, who updates her on the tempestuous events she's missed. Upon receiving some unexpected good news, she sets out to find Lila, whose circumstances have seen a dramatic change.

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.