If you're ever on vacation in Sweden and you're met with smiling women clad in flower crowns, you might want to turn back. Things might get ugly.

At least, that's the message that the trailer for the upcoming thriller Midsommar sends. That, and you probably shouldn't partake in any sort of weird concoctions strangers give when they look suspiciously cult-like.

Fans of director Ari Aster's Hereditary will no doubt find thematic similarities between the two films, which both feature a fantastical, surrealistic air to them. This particular movie looks like the uncomfortable cult like atmosphere of The Wicker Man joined forces with the supernatural lilt seen in Aster's previous movie, and it looks absolutely terrifying.

The official synopsis reveals the movie follows a couple on vacation to a Swedish village that takes a "sinister turn" when the townsfolk invite them to experience a "series of rituals" that somehow involve a ton of weird flower crowns and screaming at the top of your lungs behind a concrete wall.

The trailer begins innocently enough, with a flyover of the couple presumably on their way to the Swedish village. Probably should have turned around there. They have a brief chat about some sort of "special thing" planned during their trip, to which an unnamed man clarifies it's a "crazy, nine-day festival" that happens once every 90 years.

The dizzyingly bright yet sinister clip cuts to a group of women, all clad in cheery white and pink, with flower crowns and braided hair. One woman, who appears to be some sort of leader, looks earnestly into the camera, speaking on what we believe is the "ritual" the film's built around.

"You can't speak. You can't move. But this opens you up to the influence and it breaks down your defenses," she explains.

"Trust me," she says softly with a disarmingly innocent voice. "You're gonna love it." From what we can surmise, it looks like the festival somehow involves consuming some sort of substance that either immobilizes you or puts you in some sort of trance to welcome "the influence" in, whatever that means.

And that's around when the trailer continues to go off the rails. We see a person with a severely disfigured face, festival-goers smearing blood all over a rock, and plenty of shots where it certainly seems like everyone is tripping on some sort of weird substance or losing their minds. It isn't clear what's going on, but it sure does look fascinating.

The film's got quite an all-star cast as well, bringing actress Florence Pugh together with Jack Raynor, Will Poulter, and William Jackson Harper. Pugh was seen most recently in Fighting With My Family, and will also be appearing in the upcoming rendition of Little Women from Greta Gerwig.

It's the end of the trailer, though, that raises the most questions.

Midsommar is set to debut in summer 2019.