This well-done document provides both information and human interest in its two stories.
Told in parallel, we follow two Jehovah's Witnesses. Joseph Kempler is a Jewish survivor of the Holocaust. He lost his faith as the deaths mounted and the horrors of the concentration camp unfolded for him. Yet in his camp, a separate barracks housed the Jehovah's Witness prisoners, partly to segregate them from the non-Aryans and partly to reduce the proselytizing. These were political prisoners who by following the tenets of their religion refused to swear allegiance to the Fuehrer and the Fatherland. They could leave if their would sign a "loyalty oath". As Joseph lost his faith, he become aware of these protesters, was able to attend clandestine meetings, and eventually took on their religion. We are told his story, including his reconciliation with family members (including a daughter he had pretty much abandoned).
The other story is about twenty-something Seth Thomas, who follows the faith along with the rest of his family. His "auto de fe" comes about with his need for a transplant to replace his (congenitally) diseased liver. He can't have blood products, so the medical establishment won't do the transplant. Eventually UCLA (?) agrees to do an experimental bloodless surgery. With huge risks, he agrees; and his father will provide the partial liver donation. The whole family is faced with the risk of losing two members but are steadfast in their belief that's it's the right way to live (or die).
A lot of history is filled in around these two stories. We find how many of our rights are due to the fights the Jehovah Witnesses have undertaken: they do not vote, they do not protest(?), but they do litigate.
If you are the type to answer that particular knock on the door with "No thanks, get lost", this movie will make you want to ask a few questions, if for no other reason than to exercise nearly-found respect.