Alex Garland has officially learned how to stick the landing.

His first two filmed scripts, 28 Days Later and Sunshine, were provocative sci-fi stories that took major left turns late, and not always for the better. But his Academy Award-nominated screenplay for Ex Machina, which he also directed, proved he was capable of taking a story from A to Z and wrapping it up with a bang.

And now, Annihilation reinforces his credentials as—at worst—a tip-top sci-fi guy. It's not a step forward for Garland so much as a sidle; several scenes feel like explicit near-recreations of moments from his previous work. But, given its dreary February release date and shaky looking trailer, it ends up being an eerie, enticing tale of survival that could've easily gone off the rails with a lesser hand in charge.

Natalie Portman stars as Lena, a biologist who is swept up in an alien "assault" on Earth when her husband (Oscar Isaac) reappears 12 months after embarking on a secret mission. He and his team were inside the Shimmer, a expanding bubble on the coastline that seems to be warping all life within it. Fortunately, Lena is one of those biologists who is also a soldier, and she joins an all-female team that enters the Shimmer to determine its reason for being.

The team includes Josie (Tessa Thompson, adorned with spectacles to indicate she's The Nerd), Anya (Gina Rodriguez), Cass (Tuva Novotny), and Dr. Ventress (Jennifer Jason Leigh). We're given very little information about the group; it's implied that they all have nothing to lose, and they're entering the Shimmer because...why not? This makes them dispensable but also reinforces the Shimmer's status as an unknowable entity, one that disappears entrants and is slowly breeding desperation among those studying it.

Having women occupy these traditional action movie roles (nerdo, crazy one, mysterious leader) freshens them up a tad, but it's a shame that great actresses like Thompson and Rodriguez don't get much to work with. This is the Portman show, with the occasional strong appearance from Isaac and some expert glowering from Leigh. And the Oscar-winning actress proves up to the task, appearing equal parts badass and desperate, willing to venture into the unknown but also deceive her partners when necessary. You're not entirely sure if she's worth rooting for, and that feels like the point.

What the team encounters in the Shimmer is best not spoiled, but suffice it to say that one particular sequence in Annihilation's middle chunk may be the scariest in recent memory. Garland knows to make a strong visual count, but here he brings other senses into the mix to craft something truly unique. The mark of a good sci-fi creature is when the wholly unrealistic still terrifies, and this is the stuff of nightmares for sure.

Alas, the emerging writer-director is not quite a master of expository dialogue; the reveal of one character as cancer-stricken might've been better if she just announced it aloud a la The Room. And what appears to be a dream sequence that elevates an irrelevant character to plot prominence turns out to be reality, which muddies the waters in an intriguing but jarring fashion.

That said, this movie exists to service sci-fi fans who are looking for something a little unexpected: A terrific female cast, some very scary monsters. It doesn't ask big philosophical questions like Sunshine or Ex Machina, but it does paint alien invasions in a whole new light. Maybe there's no grand plan for humans to thwart; the invaders could be as confused and aimless as we'd be after crash landing on an odd planet. In the end, it's all a matter of interpretation.

This is all capped by a final scene that raises just as many questions as it answers, but in a good way. You can feel rosy and warm about it, or you can assume our ultimate demise is nigh. Either way, Garland sticks to the ideas that got him there: the Shimmer is about reinvention, which his characters all crave. The ones who are lucky enough to receive it have a new lease on life; what they do with it is up to them.