The stereotype of the serious, efficient German fixated on doing everything in the absolutely correct manner is taken to often hilarious extremes in this bitterly black comedy.

Mux (Jan Henrik Stahlberg) is a self-appointed vigilante with a video camera. He spends his day catching people performing petty misdemeanours like jaywalking and littering, records the "offender" and files them away in a video library.

Overwhelmed by his workload and eager to write down his ideas in a "manifesto," Mux hires an assistant, the taciturn Gert. Gert, we are told, had the worst CV of all the job applicants but his loyal, hangdog expression reminded Mux of his recently deceased pet. Such is the logic of Mux.

At first the duo's crusade to bring "a sense of purpose and responsibility" is comic, and faintly admirable. But as Mux escalates their activities to include more unsavoury criminals and more unorthodox and violent punishments, the comedy takes on a more unsettling tone.

In a parallel of Germany's most infamous historical figure, Mux's zealousness leaves him blind to his own transgressions.

To the filmmakers' credit the story keeps you gripped as it grows more extreme and weird. Director Marcus Mittermeier, maintains a good flow to the story, intercutting Mux and Gert's footage, verite style, into the narrative.

Jan Henrik Stahlberg plays Mux with energy and panache, and Fritz Roth, as Mux's sidekick provides a great counterpoint to Stahlberg's clean cut, fervour. Stahlberg, who is also screenwriter, has imbued his flawed protagonist with just enough idealism and funny lines to keep you in there for the ride.