 It tells the story of an old miser who keeps his fiancée behind the closed door of their home for fear that she will not be faithful to him (in Cervantes's version, the woman is his wife).The opera's title comes from the large padlock that the old man keeps on the cottage door.In contrast to Cervantes's miser-centred story, "The Padlock" is centred on the old man's servant, a black man named Mungo from the West Indies, who also provides a large part of the comedy.