Professor Lucia Liguori, divorced and living in Milan, during a trip to Rome, accidentally meets Giulio Cesaroni, her boyfriend when they were kids and a widower for a few years.
Thus begins the story of the Cesaronis, an extended family made up of seven members: the two parents, her two daughters and his three sons, Marco and Rudi (the same age as Eva and Alice respectively), and little Mimmo.
Giulio and Lucia's marriage is put to the test several times, mainly by the terrible relationship created between their respective children.
A further obstacle is Sergio Cudicini, Lucia's ex-husband, who interferes so that the woman and her daughters return to him, first by unsuccessfully threatening Giulio and his wife, then by staging a fake illness.
Giulio is firmly against a possible relationship between the two, considering it morally inappropriate and potentially harmful to the family balance: he gets angry with his son, and urges him to date other people.
The young man can't stop desiring Eva until he meets Rachele, a new teacher of his with whom he begins a love affair.
Rudi and Alice, during the time span of this season, constantly argue and declare their mutual disdain, but on rare occasions they behave like brothers.
In agreement with his wife, who shares his moralistic positions, Giulio makes an anonymous phone call to the port authority in which he says that a bomb has been placed on the ferry.
The two have spent the summer apart, not because of Giulio's anonymous phone call, but because of Rachele's reappearance and an apparent reconciliation between the teacher and the student.
Eva chooses the young Cesaroni and breaks up with Alex, but the situation turns upside down, and it is Marco who verbally attacks her, feeling betrayed.
Days of clashes and teasing between the stepbrothers follow, but just when Marco wants to declare his love for Eva, she resumes her relationship with Alex.
The young girl develops a crush on Umberto at the beginning of the season, but Rudi's pranks put her in a bad light.
Antonio Barilon, the head of the family, runs a bathroom fixtures shop near the liquor store, and initially does not win the sympathy of Giulio and Cesare, but the relationship is always quite cordial.