The Endless is a rare beast. It is a low-key, laid-back horror film that is surprisingly effective. It sets up a circumstance, teases out its implications, and tightens the noose so slowly that you don’t realize that how tense you are until the noose fits snugly around your neck. And the movie, blessedly, has a knowing and dry sense of humor.

Brothers Justin and Aaron (played by director/co-writer Justin Benson and co-writer and cinematographer Aaron Moorehead, respectively) are former members of a “UFO death cult,” based somewhere in the hills of California. They have been there since childhood, until Justin drags a reluctant Aaron away from the group, and they have now been detoxed and are attempting to make their way in the modern world. They are not succeeding. Living on ramen noodles and working as a house cleaner, Aaron starts yearning for the orderly world the cult provided, along with three square meals a day. He just wants to visit for one day, to see old friends. Justin reluctantly agrees.

The compound, called Camp Arcadia, is a sly dig at millennial entrepreneurial folksiness. Cast somewhere between a summer camp and a Davendra Banhart folk festival, Camp Arcadia funds their enterprise through the brewing and selling of craft beer. Everyone seems to be very type B and chill. All of them have some sort of artistic talent: Anna makes clothes, Shane is an expert on card tricks, Lizzy likes to draw, and Hal, ostensibly the camp’s leader, is working quite hard on a heady math problem. They all are happy to see Justin and Aaron back and welcome them with open arms. They all seem relatively harmless. And they are. But why the two stay and why they don’t leave is somewhat more ominous.

Justin and Aaron’s relationship is prickly. Aaron follows Justin’s lead but resents it. Justin feels he’s more worldly than Aaron and looks out for him. Neither does a very good job adjusting to life outside of Camp Arcadia. This is the backbone of the story and despite all the weirdness that eventually occurs, and things get very, very weird, Benson and Moorehead keep the brother’s relationship at the forefront.

The Endless conflates a lot of heady themes: the purpose of existence, the desire to escape mortality, the nature of time, and, possibly most importantly, the bonds of family. It manages to be sly, funny, mellow, and still deliver chills. It has the potential to be a knotty head trip like, say, Pi or Ex Machina, but it would rather charm you and leave a little bit of warmth in your heart. The fact that it also manages to creep you out makes it a special film, indeed.