Amaro Carabel (Fernando Fernán Gómez) is an ordinary man with a kind nature who lives with his aunt and is unable to marry his fiancée since his salary is permanently frozen.
During a country race organized by his company, Carabel has a well-intentioned but indiscreet talk with one of the clients that leads to his dismissal.
He then decides that the cause of his misfortunes lies in having always behaved honestly, and announces to his aunt his intention to become an evil man.
Knowing that his aunt is taking a correspondence course in hypnosis, Carabel desperately tries to use it to hypnotize her former bosses into giving her the key to the safe.
Some time passes and while he corrects a letter he reads a message of love addressed to himself, when he looks up he finds that it has been written by Silvia, who has also got a job in the company and finally did not get married after all.