The setting is Prague in the 1860s. Walbrook plays Balduin, a handsome young student. He and his pals celebrate the birthday of the innkeeper's daughter, Lydia, for whom Balduin has affections. But into the inn walks a beautiful singer named Julia. Balduin is swept away by her charms, but winning her love comes with a price; for hovering over her life is the sinister Dr. Carpis, a Satan-like figure who's more of a human shadow than a flesh-and-blood being. Carpis helps Balduin obtain Julia's affections and financial success, too. However, the price is a heavy one, and Balduin's life soon sinks into madness and terror. This terrific movie is filled with contrasts of light-hearted gaiety and shadowy dread. Walbrook and Wieck are superb, but Loos, as the sinister Dr. Carpis, steals the show in a role usually given to actors like Boris Karloff or Bela Lugosi.