Annihilation is one of those movies that’s going to divide audiences. I’m on the side that enjoyed it. Which is no surprise, really, because I’ve liked almost everything else its writer-director Alex Garland has ever done: from his breakthrough 1996 novel The Beach (which was later turned into a film starring Leonardo DiCaprio), to 28 Days Later and Never Let Me Go (both of which he wrote the screenplays for), to Ex Machina, his 2015 critically lauded directing debut.

Much of Garland’s work has dealt with not-so-distant future scenarios where something has gone horribly awry. In Annihilation — based on the first novel in Jeff VanderMeer’s best-selling Southern Reach Trilogy — it’s the fact that an undulating pastel bubble dubbed “The Shimmer” is enveloping more and more land in the marshes of Florida, and only one of the dozens of people who have gone into The Shimmer to investigate has ever come out. That lucky (?) guy is Kane (Oscar Isaac), whose biologist wife Lena (Natalie Portman) assumed he was dead after no one had heard from him for a year.

But suddenly Kane is back and in their home, yet something is very much off about him. Soon, he starts coughing up blood and having seizures, at which point Lena is not only told about but also taken to a military post outside of The Shimmer.

There, she learns that an expedition led by Dr. Ventress (Jennifer Jason Leigh, whose wooden performance was my least favorite thing about the film) is soon heading into The Shimmer to see if they have any better luck than those who went before them. The rest of the all-female crew includes Anya (standout Gina Rodriguez from Jane the Virgin), Josie (Tessa Thompson, aka Valkyrie in the Marvel universe) and Cass (Tuva Novotny). Lena believes she can help their efforts while also figuring out what happened to her husband, so she signs up as well.

They enter The Shimmer and … yeah. Things get weird. They lose memories, they lose time, and they encounter beautiful yet inexplicably mutated vegetation and flowers and animals — not all of which are friendly. They also start learning more about each other and the reasons they each had for joining what they all knew might be a suicide mission. They conclude that one of two things happened to the previous eleven expedition teams: something killed everyone, or the team members went mad and killed each other. The women quickly encounter enough evidence to justify both theories.

The world within The Shimmer is gorgeous — I would recommend seeing it just for that aspect alone. But what I personally dug the most was how Garland unveiled the full scope of the story: through flashbacks of Kane and Lena’s life together, through assumedly future scenes of Lena being surrounded by a team of concerned-looking hazmat-suited interrogators at the military base, and through steadily alternating intelligent dialogue with stop-your-heart action sequences. Grounding everything was Portman’s layered performance, which I am surprising myself by proclaiming to be some of her best work.

What I mean is that I went into Annihilation thinking it was going to be a shoot-up-aliens type of flick without much depth. I didn’t expect it to be so complex, or that it would be the kind of movie that doesn’t serve up a lot of answers. It’s meant to make you ask questions and think. I, for one, will be thinking about it for a long, long time.