We horror-movie lovers are cheap dates. A creaking door and a shocking edit can be all it takes for us to yelp in surrender, as our sympathetic nervous systems kick in and we grab our seat arms or each other. Ari Aster, who made a splash last summer with his feature directing debut, “Hereditary,” understands the genre’s fundamentals. But his strength in that movie and his new one, “Midsommar,” is the setup, that part when he lays out his characters, their worlds and the menace that closes on them like a claw.
A cautionary tale about bad relationships and worse vacations, “Midsommar” gets its creep on early. When it opens, Dani (Florence Pugh), its deeply troubled axis, is having a lousy day that rapidly turns devastating. Her boyfriend Christian (Jack Reynor), who’s on the verge of breaking up with her, isn’t much help, though he eventually comes through. Months later Dani is still having a rough time while Christian continues eyeing the closest exit. Their uneasy dynamic intensifies and changes during a catastrophic trip to a small, strange community in Sweden, where the expected summertime fun gives way to terror.
Aster handles the windup shrewdly with a persuasive realism, a deliberate pace and crepuscular lighting. Notably, he also sets Dani’s solitary tears and all of her feelings against the solidarity that Christian shares with his buds. The guys don’t make sense as friends, which scarcely matters at that point. Aster banks on the suspension of disbelief, which is part of the delicate compact we make with horror movies. When one bro, Mark (Will Poulter), starts running down Dani, you can almost see the expiration date on his forehead. As with much in this hyper-aware movie, Mark fits the role he was created to play by motor-mouthing his way into a narratively justified demise.
The stateside stuff drags (the movie runs two hours, 20 minutes) but when the story shifts to Sweden, everything changes, including the light. With his estimable crew — the cinematographer is Pawel Pogorzelski, the production designer is Henrik Svensson — Aster creates a sun-blasted, open-plan settlement that conveys airiness, back-to-the-land self-reliance and other assorted healthy things. There’s something odd about the smattering of buildings, which are too off-kilter to pass as charming; there are too few shadows and corners to hide in. The same goes for all the smiling white people in their pretty folk costumes. They’re so welcoming, yet so vacant.