Horror thriller It Comes at Night is a nightmarish tale of things lurking in the dark and a family trying to stay together in the face of an unknown threat. Can we trust our neighbors? Even if we could or should, would we?

Paul, Sarah, and their son Travis live deep in the woods, in a sleek, modern house that’s heavily fortified against an unnamed horror. Like a child that creates rituals to protect himself from things that go bump in the night, Paul (Joel Edgerton) has created a number of rules for his family to follow. Gas masks and guns figure heavily into Paul’s plan, as does the eerie red door that serves as the only entrance and exit to their home. It’s kept locked at all times, and no one is allowed to go out at night. Sarah (Carmen Ejogo) and son Travis (Kelvin Harrison Jr.) obey the rules, and everything seems to go smoothly except for Travis’s insomnia and nightmares. This tenuous peace is interrupted when a man named Will (Christopher Abbott) breaks past their defenses and eventually convinces Sarah and Paul to let him bring his wife Kim (Riley Keough) and their small child into the fold. The treaty can’t last, of course, and it’s not long before the families turn on each other.

The first scene sets the tone for the film, when Paul and Travis take Sarah’s dying father out to the woods. The old man’s body is covering in festering sores and he’s obviously dying from whatever it is that the family has been trying so desperately to protect themselves from. Paul is steely behind his gas mask as he shoots the old man and forces a shell-shocked Travis to help him burn and bury the body. The film is strongest in scenes like this, which juxtapose the wildness of the woods with what’s left of humanity. Later, Paul and Will encounter a crashed car during an outing that has the same creepy effect. The natural world is quickly taking back what we were silly enough to think was ever ours.

It Comes at Night doesn’t have a particularly meaty narrative; this isn’t a thoughtful dystopian film in the vein of Children of Men, a terrifying and gross zombie flick like 28 Days Later, or even the twisty, surprisingly good 10 Cloverfield Lane. It’s a fairly thin story held together by the cast’s strong, quiet performances and the uncanny, airless house they inhabit, with occasional flurries of activity and violence. Although Keough is always one to watch, her character seems to exist just as a crush for Travis. Similarly, Ejogo has some strong scenes where she proves she can go toe-to-toe with Paul when it comes to steely nerves and shooting guns, but her character is otherwise limited to “wife.”

Harrison Jr. is the heart of the film. His performance stands out as audience surrogate, especially compared to his parents’ weariness and the sketchiness of the younger couple and their toddler. As Travis, he creeps through the halls and crawlspaces of their house listening to the others, trying to avoid the nightmares he has of suppurating sores and great gouts of blood. He seems to be closest to whatever It is, although — surprise — we never quite find out.

It Comes at Night is the second feature by Trey Edward Shults. His first film, Krisha, was a festival darling. On the surface, the two films have very little in common except that they both rely on an oppressive atmosphere created specifically by dysfunctional families. Without a few key horrific scenes, It Comes at Night could be interpreted as a madman’s attempt to keep his family hostage, but close quarters and growing resentments have very different ramifications in It Comes at Night than they do in Krisha.

While It Comes at Night is less of a horror film than its marketing materials would suggest, Shults makes limited but effective use of violence and light gore. Although It Comes at Night isn’t quite as striking or as intelligent as it wants to be, it’s enjoyable and there are definitely a few scenes that will keep creeping you out until late into the night.

It Comes at Night opens theatrically June 9.