Spain, late 19th century. When, in a time of great political instability, Flora, a beautiful young woman, starts working in a ministry doing a job that supposedly only a man can do, a great scandal breaks out.

Filmed in 1963, but not released in Spain until 1967, the film depicts the failed romance between a bourgeois French tourist girl and a Spanish working class boy.

In a sector of Madrid inhabited by families of a well-off class, a gang of boys and girls has continuous fun, sleep and drink, while their parents ignore practically everything. However, each of these young people has, to a greater or lesser degree, a problem. The parties and parties enjoyed by a group of young people from the upper class are the basis of the story that explains this film. Among them we find the famous couple, once happy, formed by Carlos Larrañaga and María Luisa Merlo. Directed by Fernando Palacios, and with a script by Rafael J. Salvia and Pedro Masó, " It's always Sunday " has no greater intention than entertainment, despite giving history a certain sociological touch, for that of valuing the behavior of the Youth of the time.

Evelino Galindo, the serious owner of a porcelain store, argues with the womanizer jeweler Orcajo for an insignificant game of dominoes. Evelino, enraged, challenges him the next day to a duel in the gym. But after meditating a bit he starts to get scared. That is why, with the help of his friend Leoncio, he sharpens his wit to find a way to escape from combat. However, the situation is becoming more complicated.

Three friends in love, are ignored because of their lack of gift to conquer. After learning of the existence of a school of seduction, are enrolled as students.

A salesman discovers that his wife has died under strange circumstances. Examining these circumstances, it becomes obvious to him that they were mainly caused by himself.

Inspired by the classic novel by journalist and writer Emilio Romero. Shortly before the outbreak of the Spanish Civil War (1936-1939), a group of Phalangist friends, who dream of a revolution to transform Spain, are dedicated to spreading their ideas among the population. As war begins, one of them, Lopez, is about to be shot, but is saved by a Republican. Then he joins the national side. After the war, an old comrade encourages him to involve in an operation to destroy the maquis of Asturias. Although he is married and has children, he accepts the proposal, infiltrates among the guerrillas and convinces them that he will provide weapons to continue fighting.

Afther their wedding ceremony, Fernanda and Cosme Martínez go to a luxury hotel to consummate. They receive there some gifts and they find one fabulous diamant bracalet with a note for Fernanda thanking her for unfforgetable nights. Cosme feel jelause and Fernanda offended and during their wedding night they go from one place to another to find out the misunderstanding.

A rich and famous painter dies leaving a secret that kept him apart from the woman he loved. Suspecting a family plot, she will try to unveil it keeping his death from the greedy relatives who are called in the middle of the night. She will try to find the truth before the dawn comes at last.

Rosa gives birth to a child who, by circumstances of life, is given for adoption to a wealthy family who lost theirs during childbirth. Soon, Rosa will be working for the new family of his son and, so, without anyone knowing, will give him all her love.