Two men arrive on a barren island to tend the lighthouse that will keep ships from striking the rocky coast. They'll stay there four full weeks. As they approach the structure, the men they're replacing pass in silence, heading the opposite direction. Nobody speaks. Everything is black-and-white, shot on 35mm film in a square 1.19:1 ratio to add to the general anachronistic atmosphere.

This is Robert Eggers' The Lighthouse, co-written with his brother, Max Eggers. It's the director's second feature-length film, after 2016's The Witch, an impeccable low-budget horror movie about an isolated family of New England settlers terrorized by a witch in the early 17th century. At a festival screening in 2015, documented by IndieWire, Eggers said the films he had tried to make prior to The Witch "were too weird, too obscure," and so he turned to the horror genre. The Witch earned critical acclaim, and The Lighthouse feels like the director seizing the opportunity of his success to extend beyond conventional movie-making and create something truly strange.

And The Lighthouse certainly is that. Willem Dafoe's Thomas Wake and Robert Pattinson's Ephraim Winslow embark on a terrifying, painfully circuitous voyage into madness. Neither character is a reliable viewpoint; by the end, you won't even be sure what their names are. And that small point will be the least of your worries.

It starts out ordinarily enough. Winslow, the greener of the two lighthouse keepers, goes about his daily chores with bored resignation, while Wake mostly orders him around. Pattinson's performance is initially understated; he just wants to put in his time and collect his check when it's over. Meanwhile, Dafoe's character is a cartoonish Captain Ahab (as Winslow literally points out at one point); an even sillier caricature than the sea captain from The Simpsons. But Dafoe utterly sells every word he barks or growls, whether he's recounting the story of how he got his bum leg, or cursing Winslow to a slow, watery death for saying he doesn't like his cooking, in a monologue that seems like it will never end, the camera pushing closer and closer to Dafoe's weathered, bearded face, until it has nowhere left to go, and you're left simply enraptured by this unbelievably odd performance.

The Lighthouse is undeniably impressive in its craft: The environment, the set design, the claustrophobic camerawork, the black-and-white, the inspired boxy picture, the classical, unnerving score--it all works together to create an engrossing uneasiness present from the very first shot to the moment the credits roll. But unfortunately, too much occurs in between those two points, and not enough of it actually matters.

Toward the beginning, as mysteries begin to unfold, The Lighthouse holds promise beyond its archaic aesthetic and eccentric performances. Winslow dreams of a mermaid's siren call, of soggy logs floating in the tide, and the back of a fair-haired head. He's tormented by a one-eyed seagull. He glimpses strange tentacles at the top of the titular lighthouse, where Wake has forbidden him to enter. The older keeper jealously guards the keys, along with a tome-like journal that might hold untold secrets.

The Lighthouse's big problem is that few of these enticing enigmas ultimately amount to anything, and the movie's few actual revelations come and go with little impact on the events playing out onscreen. Winslow might discover something incredible or horrifying, but after a moment of panic or ecstasy, he usually just goes back to feeding coal to the foghorn or swabbing the floors.

Winslow's solitary facade evaporates as soon as he gives in to Wake's constant pressure to have a drink together, and the movie's reality breaks down quickly from there. Yet another enticing mystery is presented when a never-ending storm prevents the boat meant to relieve them from arriving; the movie begins to ask questions like, "How long have they actually been here?" and "Is any of this even real?"

The trouble is that there are no real answers, and without resolution, those questions become trite. You might spend the entire movie waiting for a payoff that never arrives; unlike in The Witch, there's no Black Phillip moment in The Lighthouse. Pattinson and Dafoe's characters seem stuck in a loop, stranded on this rock with diminishing supplies, plagued by suspicions and hallucinations, on a bender that never ends, even when they run out of booze (kerosene with honey does the trick just as well, if not better). The plot circles back on itself without reprieve--they work, they masturbate, they drink, they fight, they laugh, they dance, rinse, repeat. By the end, all the big questions and the answers that might have been go out the window and get washed away in the stormy sea as the whole thing devolves into an aggravating--albeit mesmerizing--orgy of salty weirdness.

The Lighthouse ultimately reveals itself to be more like Darren Aronofsky's overstuffed, frustrating, and self-indulgent 2017 film Mother! than the tight, grounded, shocking thriller fans of The Witch might be hoping for. Watching The Lighthouse is a unique experience, and if the concept sounds intriguing to you, it's worth diving in just to see for yourself. But unlike The Witch, this is one movie we won't be rewatching every Halloween from now on.