The whole heaven is getting ready for Jesus' birthday - the Virgin Mary is baking cakes and the angels are rehearsing carols, only one angel is kneeling under everyone's feet - the stubborn rascal Petronel. He messes up everything and never admits a mistake, so he soon turns everyone against him. As a punishment, he is sent among the people with the task of correcting one sinner so that he does not end up like a fallen angel in hell.