An important plot point in “Arcadian,” a domestic postapocalyptic drama bearing a close resemblance to “A Quiet Place,” revolves around medicine: people needing it, others hoarding it and so on. What kind of medicine is it? What is it for? The movie doesn’t say. It comes in an aspirin bottle, and the characters just call it “medicine,” and we have to take it on faith that it’s important.

“Arcadian” is fashionably oblique, implying more than it explains. (An improvement over the expository whiteboard in “A Quiet Place,” which offered bullet-form creature data like a PowerPoint presentation.)

The story is told in a cursory way: Paul (Nicolas Cage) lives on a remote farm with his teenage sons, Thomas (Maxwell Jenkins) and Joseph (Jaeden Martell). By day they forage and scavenge to survive; at night their fortified home is besieged by feral beasts, which (it is faintly suggested) are the mutated victims of an epidemic that wiped out most of humankind.

The director, Benjamin Brewer, uses many tried-and-true tricks to conceal budgetary limitations, obscuring his monsters in shadows or putting them behind doors, banging, to make the movie feel bigger than it is. He builds tension in brief pockets of silence, and when we do see the monsters, they look quite good — sticky and spindly in a tactile way, like the aliens in John Carpenter’s “The Thing.”

But a competent director can do only so much with a poor script, and “Arcadian” is littered with shortcuts and screenwriting clichés. It is vague to the point of careless, and often seems to be inventing rules for its monsters as it goes along. We hardly need everything to be detailed. But at the very least, it would have been nice to know more about that medicine.