The unnamed protagonist of A Ghost Story looks like a melancholic cartoon character: a figure in a white sheet that extends past his feet, with two miserable eye-holes in lieu of a face. A Halloween-ish creature turned into an avatar of grief and loss, he’s played by Casey Affleck, who would be a lock to win the Oscar for Best Wordless Shuffling if such a category existed. For the 92-minute running time of David Lowery’s spellbinding movie, this spirit doesn’t do much except watch balefully as life rolls on without him.

This simplicity is at the core of what Lowery has tapped into so hauntingly—that death, for all its unknowability, is frighteningly mundane. We first meet the ghost, C, as a struggling musician, living in a rustic suburban house with his wife M (Rooney Mara). The details of their life are largely kept remote, but they have typical moments of tension and tenderness before their relationship is cut short by a car accident. C dies, but soon enough, he rises from his slab in the morgue, clad in that floor-length white sheet, and is immediately drawn back to his home, his wife, and his lost way of life.

The less you know about A Ghost Story going into the theater, the better, but this is also a movie that’s nigh-impossible to spoil, since it barely has a plot at all. In the hands of a different director, it could come off like a formal exercise, an experiment in telling a story with as little dialogue and narrative arc as possible. Most of A Ghost Story’s action, after all, is a depressing kind of voyeurism—C, standing off to the side in his sheet, watching his wife wrestle with grief and try to move on with her life. He then “haunts” the new families that move into their quaint home, an emotional ground zero that he’s inextricably bound to.

Lowery’s greatest success is in keeping this intentionally spare story from feeling like a gimmick. His debut film, the crime drama Ain’t Them Bodies Saints (which also starred Affleck and Mara) was a flawed, but gorgeous-looking take on Bonnie and Clyde, shot through with Terrence Malick-esque sun-washed visuals. His follow-up was the underrated Disney remake Pete’s Dragon, which took one of the company’s lesser-known fantasy properties and turned it into something more soulful and intimate. That film had the same emphasis on human connection that helps A Ghost Story succeed: Even as Lowery avoids giving too many specifics of C and M’s relationship, he makes sure to bind his poignant visuals to a romance that feels true-to-life.

That’s a good thing, as it would be hard to sell even the most devoted art-film fan on the plot alone, which boils down to “a silent ghost lingers in the corner, watching other people’s lives go by.” There isn’t a significant piece of dialogue in the movie until more than an hour in (when the actor and musician Will Oldham shows up to wax grandiloquently on the nature of time, mortality, and the universe). Affleck’s performance entirely relies on particular, thought-through movements—a jerk of the head, a vain attempt to grasp at something through his sheet—since he can’t even fall back on giving the camera a moody stare. Though he’s long been one of Hollywood’s best quiet actors (see The Finest Hours, which is a great performance that largely leans on watching him think), this is a much more impressive challenge.

Lowery’s fine-tuned imagery helps carry Affleck through it. The director pays close attention to the details of this ramshackle house, which begins as an emotional lodestone for C and eventually becomes something approaching a prison. A Ghost Story has a keen understanding of the human obsession with things, with details, with tiny snippets of memories—it’s not just his wife that C is trying to re-connect with in death, but the pointless details of his life, the home he built, and the million other things he’s unable to let go of.

The biggest success of A Ghost Story is that it’s neither horrifying nor quite relaxing. It’s a simple fable that ties in beautifully with so many anxieties of the modern era—fears that things will eventually be paved over and forgotten, that without some grander spiritual belief, all that binds us to the world is the people who knew us, and the things we leave behind. In scene after scene, Lowery finds the right way to balance this universal angst with tactile, memorable moments. That precise tension is why A Ghost Story will linger long after you leave the theater, not unlike a sad little man in a sheet shuffling behind you.