“Nobody joins a cult.” So say many of the witnesses and survivors featured in Stanley Nelson’s fine documentary Jonestown: The Life and Death of Peoples Temple. People do join cults, of course, and plenty of them. What Nelson’s film iterates time and again, though, is that the vast majority of cult members simply get in over their heads, and a lot quicker than one might expect.

From a church shopper’s point of view, Jim Jones’ Peoples Temple had a lot going for it: vibrant worship, a tangible emphasis on the social gospel, and genuine racial integration—the Holy Grail of inner-city church development. Jones even appeared to be gifted at healing. If one wanted to be moved by one’s faith, what more could one ask?

Perhaps that your leader not be dictatorial and sociopathic. That your church has some real safeguards of accountability. That doctrine be sound. That, for goodness sake, both you and your spouse aren’t being sexually abused by the same man. Finally, that your pastor won’t ask you for your life’s savings, move you to a foreign country to establish a religious colony and virtual prison camp, assassinate a U.S. congressman, and then lead you all in a ritual of suicide. These are some of the facts of life within the Peoples Temple.

It’s not like warning signs of such clergy abuse can’t be detected. If one “miraculously healed” woman turns out to be a church secretary in disguise, for instance, cry foul. Or, when the majority of the men in your leadership group indicate that, yes, the pastor has sodomized them, too, it’s time to call the police and run screaming in the opposite direction. And by all means, when your pastor asks you all to drink an unknown liquid and then tells you it’s poison just to see how you react, there’s a good chance that, later on, he’s going to do it for real if anyone’s still hanging around.

What’s amazing about Nelson’s documentary is not that he manages to bring details like these to light, that the entire film is pieced together from eyewitness accounts to Jones’ rise and murderous fall, or that Jones himself documented the whole charade well enough that Nelson doesn’t have to rely on cheesy reenactments. The truly amazing thing is how the film builds a narrative momentum that packs so much emotional punch even though the audience knows exactly “what happens next.” I can’t recall ever having been so moved an inexorable tragedy that I knew full well was coming. The impact is devastating—and well it should be.

I suspect that part of the film’s power over me is that it captures so perfectly the mood, style, and social context of the late 1970s, the period of my own “coming of age.” At that time, I was discovering for myself distrust of church leadership, disillusionment, and loss of innocence. I was merely grateful that my own experiences weren’t nearly so extreme as that of those poor unfortunates at Jonestown in Guyana. Still, in spite of the widespread press coverage at the time, I clearly managed to get a lot of the facts of the case wrong.

Another factor that contributes to the film’s success is how deftly and efficiently Nelson tells the story of Jim Jones’ destitute childhood in Lynn, Indiana, and his later rise as an evangelist in Indianapolis. As it becomes clear that plenty of folks are looking for “something bigger than themselves,” as former church member Deborah Layton puts it, and that Indianapolis is not ready for racially integrated churches, Jones transplants his ministry to the rural paradise of California, where he ingratiates himself with overly ambitious San Francisco politicians.

Narrative issues aside, Jonestown’s main strength is the way that it gets us to see how easily we all might ignore the warning signs, if the motivations were strong enough. Jim Jones, Jr.—Jones’ first adopted child, who was fortunately away from Jonestown at just the right time—observes simply and metaphorically, “When you live in a dysfunctional family, you think it’s normal.” And when you desperately want to belong, the willingness to rock the boat gathers some prodigious dust. It’s just so sad when the pursuit of heaven leads to loss of faith. “Now I can’t believe in heaven any more,” says Layton, one of a mere handful of survivors who took to the jungles instead of drinking the Kool-aid.

Don’t go into this film, though, thinking that this is some clinical History-channel educational opportunity. It’s truly chilling to hear recordings of Jones encouraging the adults in his flock to come on down for a drink, even as their own children lie on the ground, dead, or convulsing in the throes of cyanide poisoning.

Jonestown is a nightmare of the worst—and best—kind, one that might induce palpable guilt in anyone who has ever kept silent about wrongdoing in the Church.

I expect that’s the vast majority of us, much to our collective shame. Speak up, for God’s sake.

Jonestown is unrated. The film includes some rough language and a great deal of frank talk about sexual abuse, though there is little that is visually graphic—so I suspect that the film might be roughly equivalent to a PG-13. I strongly advise, however, against screening this film for impressionable children of any age. Even with parental supervision, it could be traumatizing. For teenagers and young adults, a group setting with planned and structured follow-up discussion would be best. For adult churchgoers, this is as close to required viewing as you can get.

Courtesy of a local publicist, Greg attended a press screening of Jonestown.