This is a careful step by step look at the probability that AIDS started as a disease in chimps and crossed over man in polio vaccine in the late 1950's in Africa. It begins with a story in Rolling Stone back in the late 80's or early 90's that was crucified in the scientific community not because it wasn't possible, rather because it named the wrong monkeys used and attacked a pillar of the research community and then moves on from there to later investigations on the subject which show very clearly that the race to cure polio may have made us the target of something worse. Using the words of those involved as well as the papers and documentary films from the time this is a chilling look at how science can go really wrong and how scientists will circle the wagons to protect one of their own, even in the face of evidence that something is afoot.
I like the calm and unsensational connecting of the dots that is used to lay out the case keeping everything on a level playing field, even at the end where the film makers say flat out that short of ever coming upon a sample of the drug from that time we will never know if this is a source of the HIV/AIDS virus. However there is enough circumstantial evidence to make you reasonably sure that they have gotten things right. (an interesting note is the quoted exchange of letters between competing scientists where one warns that the other that his vaccine appears to be contaminated with an unknown and here to fore never seen before virus, a warning that was completely dismissed).
See this movie since it will open your mind.