Movies that open by announcing they are based on a true story generally fall into one of two camps, overly sentimental awards-bait dramas (generally starring a beautiful actress dressing down) or lurid genre fare hoping a faint connection to reality will help compensate for ludicrous writing. Then there’s Compliance, a movie with a connection to reality that makes it infinitely more disturbing. Based on a genuine prank phone call that escalated into psychological and sexual abuse, the fact that it’s genuine ensures that the most outlandish moments land because sadly and somewhat inexplicably, they happened. If you’ve heard the story, there’s not much that will come as a surprise. Yet, there’s big difference between reading a Coles Notes version in a news story and being stuck with the victims in real time as an uncomfortable situation spirals out of control.

The setting for one of the most psychologically disturbing films in recent years is oddly a fast food restaurant called ChickWich. The opening scenes follow the sad and gently comic lives of the employees, focusing in on teenage high school sweetheart Becky (Dreama Walker) and her oddly committed manager Sandra (Ann Dowd) who’s quietly jealous of Becky’s youth and cell-phone enhanced sex life. Though unfailingly polite, Sandra is one of those sad people who uses the meager authority she has in life as a means of making herself feel powerful if only for even a second, and she gets the opportunity to flex that miniscule muscle after an unexpected phone call.

The caller (Pat Healy) presents himself as Officer Daniels and claims a complaint was made about Becky stealing from a customer. On the police officer’s order, Sandra takes Becky into a back room where the severity of the situation is explained to both of them over the phone. Sandra is instructed to search Becky for the money and when there is none to be found the young girl is strip-searched with her clothes taken to the manager’s car to be picked up later by the police. It sounds implausible, but through the carefully constructed conversation everyone involved seems to think they don’t have a choice. The situation escalates for hours, male employees are brought in to watch Becky and, well, things get worse.

What’s most remarkable about writer/director Craig Zobel’s sophomore effort (following Great World of Sound) is the way he sustains so much suspense and tension out of a few characters in a single room with the villain on a phone miles away. There’s no overt violence and even the most humiliating and distressing scenes are shot tastefully, often occurring off camera. Yet through the intense psychological torment of the situation, the incredible naturalistic performances (especially Walker’s powerless confused teen and Dowd’s villain by circumstance), and Zobel’s carefully controlled shooting techniques, the film has an emotionally visceral quality that’s hard to describe. It’s all very low key with even Healy’s telephone tormenter coming off calm and calculated. It’s the subtle menace that makes the viewing experience so powerful and led to the actual event happening in the first place. When Compliance premiered at Sundance, it was a controversial screening filled with walkouts and angry viewers claiming exploitation and misogyny. There’s nothing about the movie that’s deserves those classifications. It’s just such an appropriately uncomfortable viewing experience that it’s easy to see why some viewers might lash out simply because they don’t like being forced into those emotions for even 90 minutes.

What the caller exploited and Zobel explored is the sad side of human nature that leaves so many people open to being controlled by authority. Everyone in the movie does what they do without question simply out of fear of angering either the phony cop or fast food management. What happens is unthinkable and probably would have been stopped if it was requested instantly, but with careful execution and manipulation it’s amazing what people can be talked into. Consider it a horror movie for the polite, proof that guiding behavior based on pleasing others is a weakness rather than a virtue. That’s something that the filmmaker hammers home with a brief coda showing Sandra as someone who suffers from the same weaknesses after the event and that defense mechanisms like smiling through discomfort or quietly submitting to authority are conditions that can’t be unlearned.

It should be pointed out that Compliance is such a small and specific movie, it’s easily susceptible to over-praise. Acknowledging the strengths of Zobel intense little yarn is important, but with the understanding that this isn’t the most disturbing film you’ll ever see and one that takes place almost entirely in the back room of a fast food restaurant. Going in expecting too much would lead to disappointment from such a delicate little psychological thriller. Go in and accept the ride and you might not “enjoy” what you see, but you’ll certainly get your stomach tied into knots and never forget it. That isn’t the most pleasant viewing experience, sure. But sadly films that provoke such intense emotional reactions aren’t too common.