The documentary Knocking, which screened at AFI Dallas, is all about the Jehovah's Witnesses -- but never slides into preachiness or snarkiness. The film just barely over an hour, but we are presented with a general history of the religion as well as an in-depth look at a few specific members with interesting situations combining religion and family, or religion and health. The movie opens with a few TV clips from The Simpsons and David Letterman reminding us of how Jehovah's Witnesses are frequently portrayed (and mocked) in society, followed by a voiceover from co-director Joel Engardio, who informs us that his mom was a Jehovah's Witness, and while he did not follow her faith, he did want to explore it journalistically. The voiceover is used sparingly; most of the time we are hearing from specific documentary subjects.
The two main Jehovah's Witnesses in the film come from very different backgrounds. Seth Thomas is in his early twenties, lives with his parents in Plano (a suburb of Dallas), and goes door-to-door with his dad to spread the word about their faith. Seth also has a rare liver disease and will eventually need a transplant, but Jehovah's Witnesses believe that blood is extremely sacred and condemns blood transfusions. Seth is trying to find a way around the problem. Joseph Kempler, on the other hand, is from Poland, a survivor of multiple concentration camps in WWII. While in the camps, he encountered the Jehovah's Witnesses, who would not give up their religion even when promised release from the camps. He was so struck by their faith that he converted from Judaism after WWII. His daughter (by his first wife) and her family are Jewish; his second wife and their sons are Jehovah's Witnesses. Joseph wants to unite both families despite their religious differences.