In Prague, dashing fencer and university student Balduin (Conrad Veidt) meets engaging stranger Scapinelli (Werner Krauss), unaware that he is the devil. Knowing that Balduin is humiliated by his poverty, Scapinelli provides an introduction to an heiress. Balduin then responds eagerly when Scapinelli offers him 600,000 gold pieces for anything in his bare room. When the devil selects the student's reflection in the mirror, a nightmare opens up for Balduin as his "doppelganger" is set free.