Laura Dal Fiore is a separated mother of two children, Emanuele and Nina. Their life flows peacefully until Paolo Giorgi, a widower, moves onto her landing with his teenage daughter Cristina. The two families, with opposite habits and tastes, end up hating each other.

Paolo has lost Laura's phone number and is desperately looking for a way to find it, while she disconsolately awaits a call from him. Fortunately, the colleagues of "Tu donna" intervene to resolve the situation. But will the magic of their first meeting make the two digest the discovery that they are each other's hated neighbors?

After discovering that Paolo and Laura were neighbors, advised against by their best friends, they decided not to continue their acquaintance. The situation is aggravated by the continuous clashes at school between Emanuele and Cristina, which even end up in front of the principal. Attempts at apologies and reconciliation seem to fail miserably and Laura ends up accepting an invitation to dinner from Sergio, Nina's teacher.

Paolo and Laura have been secretly seeing each other for ten days, but they still haven't been able to make love. Both would like to, but, confused by Monica and Michele's well-meaning advice, they are afraid to take the initiative, and when they finally decide, they can't find the right place.

Paolo and Laura are now a steady couple even if they continue to hide from their children, thus accumulating excuses and lies. However Cristina, by chance, sees her father kissing her neighbor and is shocked, so much so that she tells Emanuele, who begins to investigate.

To improve the situation on the landing, Laura decides to organize a dinner with Paolo's family, but things don't go exactly as hoped: Emanuele extends the invitation to the grandparents, the sweet Mario and the cruel Clelia and Cristina calls the elderly aunts Filomena and Sofia. Laura herself also thinks about expanding the number of guests, inviting Monica and her sister Stefania, a woman sui generis, and Paolo who brings his friend Michele. With all this confusion the dinner turns out to be an absolute fiasco.

Laura and Paolo finally manage to sleep together for the first time, but Emanuele and Cristina do everything to make the situation complicated. The woman, seized by an attack of acute jealousy, begins to see the ghost of her neighbor's wife.

It's time for Paolo too to come to terms with a ghost from the past: Laura's ex-husband, Riccardo Balestrieri, a successful writer, is returning to Rome for Christmas and will be a guest at the Del Fiore home. Laura's reassurances are useless, her new man doesn't seem to like this thing.

Christmas is approaching, and Paolo suggests that Laura spend it together, but Riccardo's arrival has upset all of the woman's plans, also because on December 25, Riccardo plans to give Emanuele a little speech. Paolo, fed up with Laura's ex-husband and disappointed by her behavior, is offended.

Emanuele cannot accept his father's revelation and refuses to speak to his parents. Even Paolo, after an initial moment of euphoria, begins to wonder why Laura has hidden this truth from him for so long.

Emanuele is increasingly in crisis and is starting to have problems at school too. Clelia suggests a psychologist, but Paolo advises Laura to be patient. After a day in the countryside with grandfather Mario, things seem to have settled down, but the next day Emanuele secretly waits for Peter, Riccardo's partner, hits him on the head with his helmet and runs away.

Peter is rushed to hospital while Emanuele disappears without leaving any trace. Paolo also disappears, for just one night, and thanks to Natascia who, feigning a breakdown in the car, blocks him in a country house for the umpteenth, useless attempt at seduction.

Paolo and Laura have decided to move in together, but they don't know how to tell their children. And they don't even know how they could take the news of the pregnancy. Between Laura's nightmares and Paolo's impediments, neither of them is able to speak to either Cristina or Emanuele, but time is running out and the baby bump grows.

Paolo, Laura and the boys begin to savor the joys and problems of the new coexistence as a single extended family. Meanwhile, Giulio and Stefania organize their surprise wedding and Paolo's aunts, after discovering that their cooking is bad, decide to take a course to learn how to cook.

Cristina can't believe that Davide Palmieri, the most handsome boy in school, has fallen in love with her, and tries to keep her story hidden from Paolo, whose overprotective father's reaction she fears. When Paolo discovers the two at home, however, he responds in a completely unexpected way.

Employment is now in the hands of Emanuele, who is becoming a point of reference for the whole school: a unique opportunity to affirm his identity among his classmates after years of anonymity. On the other hand, the occupation is offering Cristina another opportunity, that of sleeping one night with Davide. And to make love to him for the first time.

To have more time to spend with her Davide, Cristina asks Emanuele to extend school work by one day. Monica is delighted with her story with Ermanno and she would like to organize a threesome with Michele, to thank him for having organized the meeting. But the man has understood that he loves Monica and would like to refuse.

Laura has to deal with a terrible reality: she has lost her child while Paolo, desperate, doesn't know how to console her. Monica, suspicious, asks Ermanno to reveal the whole truth about their meeting and discovers that Michele has a hand in it.

Depressed, Laura no longer leaves the house except for walks with her little daughter and thanks to a meeting in the park she is convinced to return to the editorial office where she discovers, by chance, that her sister Stefania is expecting a child.

Laura is in crisis and Paolo doesn't seem to notice it, continuing his life as if they hadn't lost the child. When the woman breaks out in front of her partner and the gynecologist, the two start a furious argument in which Laura blames Paolo for what happened. Their story seems to have come to an end, as well as that between Cristina and Davide.

Just as in the Del Fiore-Giorgi house a damp spot expands, looming over everyone's heads, so the crisis between Paolo and Laura worsens, shattering their relationship. The only solution the two can find is to raise the demolished wall and each return to their own apartment.

Paolo and Laura go back to living in two different houses, Cristina is in Rome and Davide is in Athens, Cristina, Emanuele and Nina are no longer siblings, Michele and Monica are divided: nothing goes as it should. And Paul only makes the situation worse.

Laura hates Paolo because she is convinced that he cheated on him with Natascia and does everything possible not to meet him. Repenting for what happened, Giorgi finally realizes his feelings and is determined to ask Laura to marry him. Meanwhile, Del Fiore and Riccardo spend a night of passion unaware of Peter, the man's American companion.

While the preparations for the wedding are in full swing, Laura is very agitated: should she or shouldn't she reveal to Paolo that she has cheated on him with Riccardo? Monica and Riccardo himself advise her not to ruin the moment but, the night before the wedding, the woman confesses everything about her.

Paolo apologizes, but he just can't bring himself to marry Laura: he continues to imagine her in bed with Riccardo. So he leaves, leaving her at the altar. Laura can't believe it: she gets into a sort of hysterical fit, but then she can't help but surrender to the evidence of it.