Summer. Muggy weather. Examinations. Miguel, a studious young man of normal habits, has brilliantly finished his degree in Law and is congratulated. His colleagues have had different luck. One student, frivolous girl, suspended/failed, has organized, nevertheless, a party at her country house on the outskirts of Madrid. The party, of modern tone, bewilders/stuns the friends, disturbs/upsets even the most formal. Miguel, who has come to it with his fiancée Cristina, and Manolo with his girlfriend Luz, have as much fun as other young people of less scrupulous behavior; so that, upon returning to the capital, paired off, both couples succumb to temptation, the irreparable happening. Then the boys appear sincerely sorry and fearful of the consequences. Then is described the frank immorality of much of the business of the day, personified by one such don Leandro, head of a real estate company that operates irregularly, by those who want to get mixed up with the father of Miguel, who is legal adviser to a Bank and a person of great integrity. For her part, Cristina, after the summer, is planning travel to North America; Manolo confesses to Miguel his indiscretion, and Miguel, who is not less regretful, advises him to declare his fault to the parents. Don Leandro, with one of his diabolic projects, attracts Miguel, the new lawyer, through the trickery of Merche, the mistress of don Leandro, and not only dazzles him with an advance, but with another in favor of the father, not that he should know. Miguel, pressured by Merche, falls in the deception. Manolo and Luz let the parents know their true situation, without which they would have, far from it, a drama of what happened. Merche has fallen in love with Miguel, which provokes the jealousy of don Leandro, and the spite of her makes her at last discover the state of ruin that is the property company of don Leandro. Also come to light the bad tricks of the businessman for involving Miguel and his father. Such disaster clarifies and resolves the situation, and Cristina now will not go to North America to escape her guilt, because a new life opens up before them, full of hope.