We have mapped the Earth’s surface, but the creatures that live on it continue to elude us. Every year brings news of thousands of newly discovered plant and animal species, some large (a new kind of orangutan was confirmed last year), some small (the dragon ant of Papua New Guinea) and many whimsical, like a spider that looks like a Harry Potter sorting hat, named Eriovixia gryffindori. The biosphere will always surprise.

So perhaps the root of the story that is Annihilation is not as farfetched as it might at first seem. The first third of the Southern Reach trilogy, written by Jeff VanderMeer and loosely adapted for the screen by director Alex Garland (Ex Machina), it imagines a corner of Florida where biology has run amok, creating monstrous creatures and playing havoc with radio waves and even the brainwaves of those brave or foolhardy enough to intrude.

The latest team to enter “the Shimmer,” as it’s become known, is led by psychologist Dr. Ventress (Jennifer Jason Leigh) and includes a paramedic (Gina Rodriguez), an anthropologist (Tuva Novotny) and a physicist (Tessa Thompson). As the team’s only Oscar-winner, Natalie Portman gets top billing on the poster. But her character also has an interesting background, being both a biologist and a soldier. And her husband (Oscar Isaac) was the only member of a previous team to return, although something about him is off-puttingly different.

The screenplay, a little out of chronological order as though refracted through a prism, throws this team and viewers alike into a confusing but captivating mystery. Three or maybe four days into their trek through the Shimmer, the women realize they’ve completely lost track of time. They come across a weirdly, wildly overgrown and hard-to-kill crocodile. Later they will be visited by a bearlike creature that is almost guaranteed to make a return appearance in your next nightmare.

Meanwhile, the film’s soundtrack teases us with familiarity, only to yank it away: acoustic guitars one moment, the next it sounds like a drunken church choir trying to sing during a thunderstorm. There’s even a love song, Helplessly Hoping, by Crosby, Stills & Nash.

The novel and the movie exist as separate and equally enjoyable entities. I scurried out to buy a copy of the book after watching the film, and found it refreshingly unique. Garland says he read the source material but once and then set it aside and basically filmed his memory of the experience of reading it.

The result is the feeling of entering a dream or a trance, but the enigma never feels capricious. There’s an underlying, fractured logic at work here. Note, for instance, the weird deer that Portman’s character sees moving in perfect unison, and keep an eye out for other duplications and replications. Annihilation is a film that doubles down on both its science and its terror.

The actors do a good job of inhabiting the twilight zone between professional curiosity and personal fear, each one clearly trying to make sense of the oddities that surrounds her, and suppressing the amygdala’s fight-or-flight messages with varying degrees of success. The all-female cast is lifted from the book (published in 2014) but feels oddly of-the-moment as Hollywood continues to grapple with #TimesUp issues. Refreshingly, little is said of the team’s same-sex makeup. What do they have in common? They’re all scientists.