The plot centres on Nicola Pischella, a dentist known to be a ladies' man who regularly cheats on his wife Lucia, arousing her jealousy between visits to his dental office. Things get complicated when Saverio, an eccentric old relative of Lucia's, arrives at the Pischella house, claiming to be ill and close to death. He promises to leave a generous inheritance to Lucia in exchange for hospitality and assistance.
To care for the elderly relative, Angela Della Torre is hired as a night nurse. Her beauty catches the eye of Carlo, a shy young student son of Nicola, but Nicola himself and his assistant Peppino also feel attracted to Angela.
The story further complicates with misunderstandings, betrayals and mistaken identity. Added to this mix are Zaira, Nicola's historical lover, and a provocative neighbour. Meanwhile, Angela starts an affair with Carlo, while new truths emerge about Saverio's true identity. It turns out that he is not Lucia's real uncle, but an impostor who had broken into her house to steal a precious diamond hidden in a chandelier.