Pierrot et Pierrette, brother and sister, live in a caravan with their grandfather, the former ringmaster of a circus. To earn a living, they sing in the streets, and their lives are happy. But a charitable lady interferes, determined to put grandfather in an old folks' home and the children in an orphanage. Pierrot and Pierrette run away, and fall into the hands of a travelling vendor who wants to use them for burglaries.