Fritz Lang's first sound film is now regarded as an Expressionist classic. The city of Berlin is being terrorised by a notorious child molester and, frustrated by the failure of the police to catch the culprit, the underworld criminals organise themselves to hunt him down. Peter Lorre portrays the snivelling, compulsive psychopath in a role that typecast him for life and the film was remade in 1951 by director Joseph Losey.