For many horror fans, much of their thinking about The Exorcist Iii is tied into That One Scene. It may be the scariest movie scene ever, and that’s saying a lot for a movie that’s the second sequel to what many call the scariest movie ever. But it’s not a meaningless “gotcha” moment; by the time The Exorcist III gets there, it’s laid the groundwork for the viewer to understand, if not anticipate, that the unimaginable can happen to its characters.Released in 1990, The Exorcist III was written and directed by William Peter Blatty, who won an Oscar for adapting his 1971 novel into the screenplay for William Friedkin’s 1973 Exorcist. For part three, he adapted his 1983 sequel novel Legion (we will acknowledge The Exorcist II: The Heretic by noting it has its own io9 retro review, and leave it at that); in 2016, a director’s cut version was released, thankfully ahead of Blatty’s passing in 2017. But no matter which version you dig into, and no matter if your interest in The Exorcist III was first piqued by talk of That One Scene or the memes that emerged after last year’s Dahmer - Monster: The Jeffrey Dahmer Story, it remains a triumphant horror sequel. It’s not a retread of The Exorcist—which The Exorcist: Believer, out October 6, looks like it could be—but it might be just as disturbing. It might be more disturbing.From its first scene, The Exorcist III keys in on the psychic reverberations of what happened in Georgetown 15 years earlier. We see Father Dyer (a character from the first Exorcist, here played by Ed Flanders) standing at the top of the stairs where Father Damien Karras (Jason Miller) took his fatal plunge during the climactic exorcism. We see Georgetown homicide detective Bill Kinderman (another returning character, also played by a new actor: George C. Scott) holding a picture of Karras, and then we cut back to those damn stairs, the bottom this time, as “Tubular Bells” kicks in. Throughout the sequence, and then throughout the movie, we get the sense that something unnatural is in the air—a literal ill wind that dissipates fog, shoves open doors, carries otherworldly whispers and growls, and whooshes through enclosed settings where no breeze should be.With a friendship built upon the grief they share over Damien’s loss, Dyer and Kinderman meet on the anniversary of his death to go to the movies. This year’s pick is It’s a Wonderful Life, a choice that reverberates with horrific irony as the movie progresses. Kinderman’s got a new case to worry over, as bodies mutilated in theatrically sadistic ways (seriously, Hannibal Lecter would take notes; no wonder Jeffrey Dahmer did) start accumulating. When Dyer’s targeted in a gruesome manner, it gets more personal for Kinderman than it already was, and he begins to suspect the impossible: the culprit is the Gemini Killer (Brad Dourif), a serial slayer who died in the electric chair... exactly 15 years ago. How does it tie into the mysterious long-term patient at the Georgetown hospital who was picked up in an amnesiac, near-catatonic state... exactly 15 years ago? And why does “Patient X” look identical to the late Father Karras?If it were just a crime drama with the added attraction of carrying over plot elements from one of the best-known horror movies ever, The Exorcist III would be an entertaining and worthy successor. But it has its own doom-laden energy that feels more akin to Friedkin’s 1970s release than any of the jumpy thrillers that became a 1990s trademark. Through carefully off-putting editing and camerawork, and slippery characters in the supporting cast (especially Nancy Fish as Nurse Allerton), The Exorcist III warns that the viewer has to pay close attention; the demonic forces poking into the lives of Kinderman and company mean that we can’t always trust what we’re seeing onscreen. There are surreal dreams that bleed into the movie’s reality, and even the things that happen when everyone’s awake tend to drift into the unbelievable. The world of The Exorcist III is a tainted one, with dark forces scheming to settle unfinished business—but, helped in great part by Scott’s performance as the blustery but morally airtight Kinderman—it somehow doesn’t feel like a world drained of all hope.It is, however, stuffed with operatic horrors that almost take it over the top so many times. The Exorcist III is saved from being a splatterfest by deploying restraint (the Gemini’s mutilated victims are, for the most part, kept beneath blood-spotted sheets), saving the most dramatic juice for, well, That One Scene. The build-up is agonizing—if you know it’s coming, you’re just waiting and waiting; if you don’t know it’s coming, prepare for the jump scare of your life—and lasts a generous five to 10 seconds at most. The killer’s favorite weapon, hefty shears that can sever a human head from its body in one chop, are almost comically freakish; they’re something Jason Voorhees might keep in his tool belt. But in the context of The Exorcist III, they perfectly establish a sense of mounting dread just thinking about how the killer is using them, so that by the time you see them in action, the payoff is perfection. The Exorcist III is widely available to stream on various platforms, including Prime Video, Shudder, and Peacock.Want more io9 news? 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