The catalyst for much great horror is confusion and uncertainty. The unknown and unpredictable is inherently scary, because there is no protocol, no expectation on which to fall back. So when weird things start to happen in a story, it’s unsettling. The way in which such a mystery is unraveled and explained goes a long way in determining how good a film a horror story really is.

Hereditary begins with great promise: a reserved matriarch of a family dies, and the two generations that come after her are left to mourn the passing and cope with their bonds. Annie (Toni Collette) never much talked to her mother later in life, despite having her live in her house alongside her dutiful husband (Gabriel Byrne), stoner teenage son Peter(Alex Wolff), and idiosyncratic adolescent daughter Charlie. Of course the house in which they live is old and vast; and that Annie’s profession is designing miniatures is a storytelling device filled with great dreadful potential.

Unfortunately that potential isn’t tapped as much as should be. What’s more, a pivotal, surprising, and indeed shocking moment in the first half of the film lays the ground for a strange, disturbing tale to follow. But it turns out the secrets left behind by Annie’s mother aren’t as novel as hoped for. It doesn’t give much away to say that the family is being haunted; Peter and Charlie see and hear their grandmother’s ghost for reasons unknown.

We have all the standard horror tropes too: a shadow lurking in the darkness quickly disappears when the lights go on. A bird flies aggressively into a window, killing itself. Moments of sheer horror reveal themselves to be dreams. And then of course there is the appearance of a mysterious stranger that known just a little too much about what’s going on. Oh, there is a seance, of course, and when Annie has ideas about what is happening, she is regarded as hysterical.

Hereditary creates an unsettling atmosphere throughout, earning much good will in the beginning by effectively setting up this troubled family and slowly revealing their past.  There is a compelling drama about trauma and familial struggles, propelled by a steady pace and great acting. Which is why it’s disappointing that the film, written and directed by Ari Aster, seems to settle into a generic paranormal story. It’s not by any means bad, but so much that seems new and weird in the beginning devolves into the familiar and trodden. There are many great individual pieces, but they don’t add up together to something greater than the parts. But it still might scare you to death; or the afterlife, as it were.