According to a press release, the film, which was written and directed by Ari Aster and debuted at the Sundance Film Festival , tells the story of a family whose "cryptic and increasingly terrifying" ancestral secrets begin to reveal themselves following the passing of the family matriarch. Throughout the bone-chilling trailer, star Toni Collette grapples with her loss while she and the rest of her family begin to unravel into chaos — we're talking people walking upside-down on walls, birds flying into windows, people getting set on fire, and a whole slew of other unexplainable events.