It tells the World War II era story of a cynical, successful businessman named Domenico, who, after meeting a naive country girl, Filumena, one night in a Neapolitan brothel, keeps frequenting her for years in an on again-off again relationship. He eventually takes her in his house as a semi-official mistress under the pretense that she take care of his ailing, senile mother. After having fallen for a younger, prettier girl and having planned to marry her, he finds himself cornered when Filumena feigns illness and "on her deathbed", asks to be married to him. Thinking she'll be dead in a matter of hours and that the 'marriage' won't even be registered, he agrees. After having been proclaimed his legal bride, the shrewd and resourceful Filumena drops the charade and acknowledges the act she put on for the child she bore him. Domenico tries to cajole her into telling him which one is his but she stalwartly refuses, telling him that sons can't be picked and chosen and that he has to be the father of all three. One of the film's more memorable moments is when Domenico is on the phone with his new flame, shortly after having married the "moribund" Filumena. As he reassures his fiancée that death is near, a wild-eyed and vengeful Filumena emerges from a curtain behind him and exclaims in Neapolitan that she is in fact alive and well — the Madonna having taken pity on her. A struggle ensues as Domenico obsesses over which son is his; Filumena reveals that his son was conceived on a night when he told her that they should "pretend they are in love". She wrote the date on the 100 lire note he gave her, now in her locket, and after which she became pregnant. If Domenico can remember this date he will know which is his son, but he cannot. He visits all three young men at work, searching for clues, but Filumena refuses to reveal any more. When they meet again, he threatens to gothe boys and tell them things she would not have them know. She says if he does she will kill him. They argue ferociously but finally fall into each other's arms. At the church, the boys wait, and Domenico arrives. Domenico mentions that, because he will be marrying their mother, he will give them his name. However, he continues to prod them for clues. Filumena rushes in, and Domenico smiling with joy, tells her how wonderful she looks. Back at home, the sons bid their mother goodnight. As Filumena sits and weeps with joy, the boys, one after another say goodnight to "Father". Domenico smiles broadly at this, and says, yes he will see them tomorrow. When Domenico asks why she is crying, she states it feels wonderful to cry.
The film was received favorably. The New York Times noted that it was the fourth quality collaboration between director Vittorio di Sica and Sophia Loren, and the second to include Marcello Mastroianni in the mix, the "warmup" for this movie having been 1963's Yesterday, Today and Tomorrow. The review described it as a "wonderfully flamboyant" film, and provided some context for the film, noting that Naples was "a quite unusual place, where the people are highly individual and may have bizarre relationships." The film was nominated for Academy Awards for Best Foreign Language Film in 1965 and Loren for Best Actress in a Leading Role in 1964. It was also entered into the 4th Moscow International Film Festival.
