Juan Fonseca works as managerial from a modern factory, where they start using a new machine that revolutionizes all known techniques. After 7 years of courtship he gets married and enter in the consumer society: car, house, TV... His wife is pregnant and the money he earns it is not wnough so he is forcer to have more tha one job. Stress will bring dangerous consecuences to his health
Córdoba, Spain. Lord Killarney, representative of the British Museum, acquires an Arabic incunabulum at an auction; but he is murdered and the book disappears. All suspicions fall on El Lince, an antique dealer with a shady background, who asks his nephew to warn Curro Jiménez.
A mature man habitually pursues young girls, for which he is abandoned by his wife. The devil intervenes, offering both spouses, separately, to regain their youth. The two agree to make up for the lost years, but the devil makes them both join the same gang for a summer. The husband, who now feels comfortable, falls in love with his wife again without recognizing her, just as she will not recognize her ex.