The business of being a fan of horror movies is a frustrating and thankless one, since they are so especially prone to being bad, but ever so often one comes along that you can stand up and cheer and point at and say "that one. That is what I have been waiting for". And oh my God, there were two of them this year at the Chicago Film Festival. I’ve already done my cooing and slavering over The Babadook, so let me now turn to a film that is almost as good, and arguably more creative: writer-director David Robert Mitchell’s It Follows.

The creativity starts right with away, with the film’s very theme: It Follows is, get this, a horror film about sexual morality. Wait, I think I got that backwards. My point being, it’s a small miracle that It Follows is able to make so much that feels so fresh and damn near unprecedented out some pretty musty ingredients: a bunch of young people right on the gradient between teenagers and adults, in the All-American Suburbs, trying to fight against an implacable enemy that kills you for having sex. But this is no knife-wielding psychopath; whatever it is, there’s not an ounce of evidence that we get to see.

After an elaborate, 360° and back somewhat pan that shows some anonymous girl running from her anonymous house, trying to escape from something we never see, we get our sense of what it can do when we see her dead, her legs gruesomely broken, on the beach. And after this opening gambit (which, honestly, I didn’t care for much at all, thinking it too glamorously cryptic and generic: I indeed spent the first several minutes of the film supposing that its wave of hype, unabated ever since its Cannes premiere, would turn out to be so much overinflated bullshit), we move onto the actual characters. First among these is Jay (Maika Monroe), who is reaching the point with her current boyfriend Hugh (Jake Weary) that the time has come to think about having sex; her other friends include Paul (Keir Gilchrist), who nurses a poorly-hidden crush on her, as well as Yara (Olivia Luccardi) and Kelly (Lili Sepe), who have some distinguishing characteristics but mostly just function as “we needed a couple more girls in the cast”, and represent the film’s most obvious shortcoming.

After what doesn’t seem to have been terribly exciting car-sex, Hugh attacks Jay with a rag soaked in ether; she wakes up to find herself tied to a chair, with Hugh taking a weirdly protective stance towards her, considering the circumstances. This is, you see, a demonstration: he wants her to see the thing that will be stalking her now, until it kills her, and then it will resume stalking him, until it kills him, and on back to the beginning of whatever. The only way to make it go away is to have sex and thus pass it forward like some hideous paranormal chlamydia. And try as hard as possible to have sex with somebody you’ll never see again, perhaps by adopting a fake name and address and ginning up a relationship with a girl from some other town. Exit Hugh the impossible asshole.

Having been convinced of its existence (it first shows up as a nude woman - it often shows up as a nude or partially clothed woman, which would maybe be a violation of the idea that it tries to be inconspicuous in its stalking, but is not at all a violation of the fact that this movie which otherwise does a great job of treating its female lead with support and respect, for a horror picture about metaphorical STDs, was after all made by a man), Jay has to work a bit to convince her friends, shortly to include across-the-street neighbor Greg (Daniel Zovatto), that she’s not going crazy, and that there really is a stalker that always changes its appearance, but nobody else besides her can see it. Once she’s successfully done that, the film becomes a glorious exercise in watching people in a horror movie apply logic and planning to their situation.

It’s blessedly intelligent, human-acting characters are one of the film’s biggest strengths, and it’s the foundation for everything else that works. For as is usually the case, it’s easier to be invested in the fates of horror movie characters when we have a reason to like them, instead of rooting for them to die violently because they are irritating generic placeholders. It’s also easier to laugh with them and feel a part of their well-worn group dynamic; and this is perhaps the most shocking thing of all about It Follows, how laugh-out-loud funny it frequently is. And not in the sense where you have a solid joke to release some of the pressure of a tense moment, but actually robust character-based humor, as though the film was secretly a comedy all along and just wasn’t telling anybody.

Above and beyond its crackerjack script, It Follows is just really damn cunningly made. It’s not scary according to the normal rules - other than the first scene where it appears as a crazy naked lady, there are no decrepit buildings, very few underlit, shadowy spaces, and nothing that looks acutely terrifying. Only one scene absolutely leans on our old friend the jump scare - though it is an exquisite jump scare, the most visceral “oh my CHRIST” scary moment in the film. Most of the film’s scariest, or at least tensest moments come from a far subtler place. The marvelous thing about It Follows is that it completely trusts us in the audience: we know the rules, that Jay is being stalked by a shape-changing human figure walking towards her at a steady gait, and it expects us to be just as keyed up about that as she is, and just as attentive to all the human figures in the background of every shot. It doesn’t need to smash cut to a figure as the score rages out on the strings. Just a nice, static wide shot, with someone walking towards Jay that she doesn’t notice. That’s all it takes for It Follows to kick off scene upon scene of the screaming heebie-jeebies.

Speaking of the score, it’s a fascinating one. Composed by Disasterpiece, it’s wildly erratic: sometimes staying low in the rumbling base, sometimes jangling along tunefully in a fairly obvious attempt to copy John Carpenter’s scores (Halloween especially, though not exclusively). And sometimes it’s outright lousy, though this is rare: but in the moments where the music decides “okay, this bit it meant to be scary”, rather than contributing to a sustained background, it goes generic and trite fast.

This isn’t the only flaw: the relative poverty of all the characters besides Jay I’ve mentioned, and there’s also a certain thinness to the films intellectual content: despite its welcome treatment of teenage female sexuality as a normal, sane, healthy thing, it’s still ultimately telling a story about how sex’ll kill ya. Worst of all, to my mind, is the ratty sound recording: in all its minimalist staging of its low-key horror, It Follows wears its low-budget production values like a medal of honor, but there’s no getting around cheap sound, and there’s shaggy, fuzzy, peaking audio all throughout the movie. It’s a dismaying and distracting limitation from a film that otherwise works as a showcase for using less to do more.

But whatever, horror movies this smart, this fun, and this actually horrifying come along far too rarely, and I have no desire to nitpick this one to death. The insights into young adulthood, coupled with the terrific thriller craftsmanship combine to make of the very best American horror films in years, and it’s as close to essential viewing for even the most horror-averse viewer as horror gets.