During a town meeting Tom decides to put a theory to the test: if human beings are basically good they will allow someone to stay in their midst without distrust. The test comes in the form of a stranger seeking asylum in their town after a swarm of black automobiles ask about her. The local residents are hesitant to grant her request, but Tom's plan to have her do chores for the town to justify her staying sways them. Their civility doesn't last long after a wanted poster is put up and authorities come around asking for Grace. Now with the town reassessing the cost of harboring Grace, she may find that Dogville's teeth are going to be bared.
By filming Dogville on a sound stage, Lars Von Trier really enhances the claustrophobia and fear that plagues Grace during her stay in Dogville. Von Trier has made more inflammatory works in Antichrist, but Dogville's horrors are much more nuanced. The fear here comes from the decent, earnest, small-town folk who are only doing the best they can for a stranger. Now that is horrifying.
Read about the rest of Von Trier's career at Movie Mezzanine