Paramount Pictures

“I don’t know.”

This statement, or variations on it, is uttered repeatedly throughout the film Annihilation, generally by characters who have returned from “the Shimmer,” a deeply weird sci-fi zone in which the customary laws of physics, biology, time, and memory no longer prevail. It is also a statement that many viewers may be inclined to utter when asked precisely what it was they just watched.

Ambiguity is not necessarily a bad thing in a motion picture. But Annihilation, the director Alex Garland’s adaptation of the first novel of Jeff VanderMeer’s Southern Reach trilogy, is so resolutely vague, so eager to confound, that its ambiguity becomes itself ambiguous. Does it intend to let viewers balance competing interpretations? Or does it simply not know what it is trying to say? Though Garland’s film is decidedly creepy and often ravishing to look at, it’s hard to shake the sense that, beneath its highbrow patina, it is an intellectual muddle.

The movie opens with a biologist, Lena (Natalie Portman), being questioned by a man in a hazmat suit. He wants to know about her experience in the Shimmer, also known as “Area X.” How long was she in there, what did she eat, what happened to the other members of her expedition? I don’t know, I don’t know, I don’t know.

Flash backward in time. Lena’s husband, Kane (Oscar Isaac) is a soldier, and he has been long missing and presumed dead. But one weekend, as she weeps inconsolably, he reappears mysteriously. (In a touch that approximates the definition of “too on the nose,” the musical accompaniment is Crosby, Stills & Nash’s “Helplessly Hoping,” and Lena sees him walking up the stairs to the bedroom precisely as the song reaches the line “Stand by the stairway, you’ll see something … ”) Is he a ghost? Has she lost her mind?

He isn’t, and she hasn’t. Kane has indeed come home, but he is scarcely a shell of his former self. His military unit had been among the first expeditions into the Shimmer, but he has no memory of the mission at all. She asks him questions about what happened. He replies with I don’t knows. It becomes clear, however, that he is severely ill. The two soon find themselves at a secure facility where a psychologist, Dr. Ventress (Jennifer Jason Leigh), explains to Lena that her now-comatose husband is dying.

Ventress also explains the Shimmer, a dome-like forcefield that arose from a meteor crash site in the wilds of northwest Florida. Small at first, it has continued to expand across the Panhandle, until it now looks like a monstrous soap bubble, colors washing wetly across its surface. No one quite knows what it is—“a religious event, an extraterrestrial event, a higher dimension,” Ventress offers. But despite repeated expeditions, “nothing comes back.” (Kane is evidently the sole exception.)

Ventress herself will be leading another team into the Shimmer shortly, and Lena, who wants to know what happened to her husband, volunteers to join. For no obvious reason at all—if the team wanted a biologist, wouldn’t they have selected one themselves?—Ventress accepts Lena’s offer. So in they go: Ventress, Lena, a paramedic (Gina Rodriguez), a physicist (Tessa Thompson), and an anthropologist (Tuva Novotny). The logic behind the all-female team is given the most cursory of nods: Well, the previous groups were mostly military men, so why not?

Once inside the Shimmer, the group observes that time seems to operate differently, and that plants and animals are undergoing severe mutations. (Lucky a biologist invited herself along!) The women are pursued by a massive gator and then, more horribly, by a huge bear-like creature that speaks with the voice of its victims, like the legendary leucrocotta. They also find disturbing remnants and recordings left behind by earlier expeditions.

This central portion of the film is by far its most intriguing. Garland maintains a persistent sense of dread as the explorers’ nerves begin to fray. Is there something in the Shimmer intent on killing them? Will they go mad and kill one another?

The visual world Garland conjures is likewise remarkable, a cunning commingling of the familiar and fantastic, the gorgeous and grotesque. Flowers blossom a tad too extravagantly, in shapes and colors that are not quite right. Trees contort into humanoid form or evolve into crystalline candelabras. Great mold-like blooms appear that are at once stunning and sickening. (One appears to have partially consumed a man.)

Alas, once our explorers reach their ultimate destination—and you will not be surprised to learn that not all of them reach it—the revelations it offers are at once mundane, largely opaque, and intermittently comical. (This may be the first time I’ve seen a film try to play the classic “mirror routine” straight.) When the interrogators we met at the opening of the film later ask Lena asked what she thinks the alien force or intelligence she encountered may have wanted, she replies, “I’m not sure it wanted anything”—which is not a particularly compelling premise for a film.

Such failures of internal logic might have been overcome if Annihilation had a strong emotional core. But it doesn’t. Apart from Portman’s and Leigh’s characters, the rest of the cast is sketched in the broadest of strokes. Leigh’s Ventress is deliberately enigmatic but, once revealed, her secret is utterly inconsequential. And while Portman’s grief and guilt—explained in part by a painfully unnecessary backstory—are meant to be a primary engine of the film, they never quite coalesce into anything moving or meaningful. This is a particular disappointment given that the actress gave, to my mind, the most grownup performance of her career as the wife of a military man lost and presumed dead in the 2009 film Brothers.

Other potential plot hooks are cast aside altogether. I have not read VanderMeer’s novel, but I know that Garland, who also wrote the screenplay, has taken considerable liberties with it. The book’s narrative framework—it is told entirely through the journal of the Lena character—is abandoned (perhaps inevitably), and with it a certain ability to provide and withhold information. Likewise, in the novel, the characters have been trained to respond to hypnotic cue phrases, among them annihilation, but this subplot, too, has been dropped. (Yes, Garland has excised the meaning of the word that gave the entire enterprise its title.) And so on.

The result is a film that has the feel of brainy, high-end science fiction, but ultimately neither the underlying structure nor content. It’s a shame, given that we are in the midst of a modest heyday for the subgenre. Garland’s previous feature, the exceptional Ex Machina, raised probing questions about the nature of consciousness and humanity—and offered clear, if provisional, answers. Likewise, Her and Blade Runner 2049 and, regarding the linearity of time, Arrival. By contrast, Annihilation raises related questions (there’s an echo of Solaris in there as well), and then essentially shrugs, asking viewers to supply their own meaning.

What precisely was Garland hoping we might take away from his film beyond a kind of moody befuddlement? To borrow a phrase: I don’t know. Worse, by the end of the movie, I didn’t care.