The libretto is based on a story by the German author Johann Karl August MusÃ us , `` Der geraubte Schleier '' ( The Stolen Veil ) , but this story only has a short outline of the plot of Swan Lake . The libretto is based on a story by the German author Johann Karl August MusÃ us , `` Der geraubte Schleier '' ( The Stolen Veil ) , though this story provides only the general outline of the plot of Swan Lake .