Dani (Florence Pugh) suffers a terrible blow when she loses her sister and her parents in one tragic night. Meanwhile, her boyfriend, Christian (Jack Reynor), has been wanting to break up with her – but now he doesn't have the heart. So, he invites her to come along on a trip to Sweden that he's planned with his friends Josh (William Jackson Harper) and Mark (Will Poulter); their other friend, Pelle (Vilhelm Blomgren), has invited them to a special festival that's only held once every 90 years. The festival seems enchanting – until a strange ritual shocks the Americans. Then people start disappearing and strange potions are served. As the festival heads toward its final day, Dani finds her fate entwined with the disturbing festivities.

Set in broad daylight, during the time of Northern Europe's midnight sun, this horror movie isn't about getting the creeps so much as it is about the slow, methodical unmasking of horrors. With Midsommer, writer/director Ari Aster (Hereditary) proves himself an upper-crust genre filmmaker, like Jordan Peele (Get Out, Us) and Robert Eggers (The Witch, The Lighthouse). He goes beyond jump-scares, hauntings, and moody atmospheres into something deeper and longer-reaching. The movie, which echoes The Wicker Man but travels in its own direction, is complex enough to consider that the ages-old Swedish rituals may actually have their own kind of logic, which might be superior to the self-serving, entitled attitudes of the Western visitors.

Yet Aster is smart enough and tricky enough that he lures viewers through Midsommar's 140 minutes with effortless grace; his characters are flawed, but they're human, and they have traits that make them endearing. Their trials and thought processes have intrinsic logic, yet the locals – clad in their white, flower-edged gowns and crowns of leaves – are also unfailingly logical. Aster matches logic with movement as he establishes his large, haunted space and moves through it as if deep in thought. (Some of the movie's huge, deliberate movements feel like the Stanley Kubrick of The Shining.) There's no place to hide here, no place to be alone. It would follow, then, that there's no place to be caught off guard. But such an idea is deceptive. In the end, like the best monster movies, Midsommar shows that monsters lurk within all of us.