Antoñito is a bachelor who works in a cabaret as a clarinetist. He has put an advertisement in the newspaper, looking for a good and honest girl, and to which responds Rocío, who escapes from her native Córdoba to hide the embarrassment of her pregnancy. The coexistence with the naive clarinetist, who refuses the insinuations of a co-worker dedicated to prostitution, who idolizes his deceased mother and keeps as a relic the orthopedic leg of his late father, is not easy. The other men will tend their ties around Rocío, that makes way in the world of the spectacle pretending to be blind. When she can no longer conceal that she is pregnant, Antoñito decides to give his name to the fruit of sin.