It usually takes the passage of time for a film to widely attain the moniker of "classic," years in which to grow in esteem and influence while carving out an enduring legacy for itself within both its respective genre and the cinematic landscape as a whole. Like some of the very best, though, "Hereditary" doesn't need years. All it needs is the two hours it takes to watch it and walk away feeling not only rattled to one's core but somehow changed. This galvanizing writing-directing debut by Ari Aster is not only one of the truest, most wrenching explorations of a family in crisis ever brought to the screen, it fast cements itself as a watermark in horror alongside Alfred Hitchcock's "Psycho," William Friedkin's "The Exorcist," Tobe Hooper's "The Texas Chain Saw Massacre," John Carpenter's "Halloween," and Daniel Myrick and Eduardo Sánchez's "The Blair Witch Project." Radical in its viciously unpredictable imagination, remarkable in its revelatory construction, searing in its unshakably raw emotions, "Hereditary" is so mesmerizingly assured in its every sequence, detail and beat it's almost unthinkable to comprehend.

In the aftermath of her 78-year-old mother's death, Annie Graham (Toni Collette) struggles over her complicated feelings of grief. She was never particularly close to her mom—before her symptoms of dementia and dissociative identity disorder worsened and Annie became her caretaker, they had been estranged for years—yet it is this lifelong disconnect which plagues her most of all. A miniature artist preparing for a gallery exhibit, Annie is up against tight deadlines with her work. Suspecting that her family—husband Steve (Gabriel Byrne), 16-year-old son Peter (Alex Wolff), and 13-year-old daughter Charlie (Milly Shapiro)—wouldn't be able to help her or understand what she is going through, she reluctantly attends a "Losing a Loved One" support group. One night as Annie prepares to close down her workshop, she thinks she glimpses her mother standing motionless in the shadows. She ultimately chalks this happening up to her mind and eyes playing tricks on her, but are they really? Charlie, a quiet, introverted child who shared a special bond with her late grandma, seems to be having her own trouble reconciling the loss. When Annie tries to have a heart-to-heart talk with her daughter before bed, Charlie's ominous question—"Who's going to take care of me when you die?"—pierces her like a stinger shooting straight to her soul.

Upon first viewing, "Hereditary" offers the icily sinister pleasure of discovery, a macabre specter's touch which lingers long after the credits have rolled and one begins to ruminate on the film's despairing tornado of events. In retrospect, the picture thrillingly deepens all the more, its portentous clues spread like breadcrumbs leading methodically into the clutches of evil. At its center is the Graham family, caught in the cogs of a malevolent destiny they neither anticipate nor understand. From the bravura opening shot, an introduction to our protagonists' idyllic woodsy home and their awakening into a topsy-turvy nightmare, writer-director Ari Aster mischievously subverts expectations with a burnt-black fairy-tale flourish. Things are not what they seem until they are exactly what they seem.

A mosaic of dread, ever rising to a suffocating crescendo, masterfully walks hand in hand with what, for long stretches, is a straight harrowing drama. Aster unflinchingly digs to the nucleus of his four lead characters and their tortured humanity. As near-insufferable guilt, remorse and anguish threaten to tear the Grahams apart, a possible light miraculously reveals itself just as altogether grimmer, more shattering forces close in. As Annie, a wife and mother who must bear the weight of her entire family while coming to terms with her own fateful misdoings, Toni Collette (2015's "Krampus") delivers a performance of harrowing, full-throated devastation, as towering as it is courageous. Gabriel Byrne (2005's "Assault on Precinct 13") is understated and deeply touching as father Steve, aiming to be a pillar of strength as the life he's built tumbles down around him. Alex Wolff (2014's "HairBrained") finds an aching, mournful gravitas of his own as son Peter, his connection to his mom frayed by a traumatic experience from his past he's never been able to shake. And Milly Shapiro (making her film debut after originating the title role of "Matilda" on Broadway) exhibits a poignantly craven vulnerability as daughter Charlie, unable to connect to others the way she did with her grandmother. In a key supporting turn, Ann Dowd (2015's "Our Brand Is Crisis") brings an empathetic spark to Joan, a woman also grappling with loss whom Annie befriends.

Early in the story, Charlie watches as a bird fatally collides with her classroom window, an eerie harbinger of the wickedness yet to come. True to this superstitious implication, there are ensuing scenes difficult to take and impossible to shake, yet one does not dare turn away. There are scenes as tough, unnerving, and even frightening as any in recent memory, their brand of scares never cheap and fully earned as the film's provocative imagery seeps underneath one's skin. That the picture is largely suggestive—it often feels like more is being shown onscreen than the reality—is a testament to the shrewd skillfulness of its makers. The sound design is mountainous in its disquieting complexity, clawing its way into one's subconscious, and the same most definitely goes for composer Colin Stetson's (2013's "Blue Caprice") sublime music score. Cinematographer Pawel Pogorzelski's (2017's "Tragedy Girls") lensing is rapturously mysterious, no frame captured by chance, each second an invitation into a panorama as spellbindingly identifiable as it is otherworldly. Adding to this uncanny sense of displacement are Annie's expansive miniature dioramas, small in size yet threatening to swallow up the Graham household one extremity at a time.

It is a tricky thing to discuss "Hereditary" without giving away its bewitching secrets and culminating impact. Each exquisite solitary moment works apart and in tandem with the greater whole as the film delves profoundly into themes of mortality, of bereavement, of inextricable genetic bonds, of familial sins of the past, of a desperate search for solace in the face of enveloping hopelessness. Capable of breaking one's heart and chilling the viewer to the bone—we do, after all, come to love and fear for the beautifully flawed, forlornly imperiled Grahams—the film transcends genre altogether, reaching ecstatic heights of pure cinema. To experience "Hereditary" is to sense something monumental being born, a quaking, foreboding, tragically humane tour de force penetrating itself squarely into the epicenter of darkness.