Perla is a teenager who has been prostituted by her mother, Tomasa and acts as a dancer in a cabaret-brothel. The pianist who plays at the venue is a romantic singer-songwriter and inveterate poet who would like to make art out of a sordid situation. When "el Marro", a sick sailor stops at the place and falls in love with the girl, the mother tries to cut off that relationship, but fails to do so. Because she knows that they are actually siblings.