No One Will Save You wastes no time getting started. After a brief setup, it gets right to the action: a home invasion that’s actually an alien invasion. What follows is an incredibly tense, surprisingly quiet mix of sci-fi and horror, just the thing for a fall evening at home.

The movie — which is streaming now on Hulu — comes via writer and director Brian Duffield, who previously wrote similar genre twists The Babysitter and Love and Monsters. It centers on Brynn (Kaitlyn Dever), a young woman who lives alone in a big, isolated house and who — for reasons that aren’t clear until much later in the story — is either ignored or hated by basically everyone in town. But she keeps herself busy making dresses, constructing a model village, and writing letters to her childhood friend.

You get just a scant introduction to Brynn and her quiet life before things go bad. At first, it seems like a burglar has broken into her house one night, but it turns out to be a tall, gangly alien with telepathic powers. It’s really creepy; the extraterrestrial moves in unsettling ways, twisting and contorting its body, and it makes a kind of clicking sound that’s very, well, alien. Brynn just barely makes it out alive.

What’s impressive about that first encounter, though, is that it’s just the tip of the iceberg. From there, No One Will Save You expands its scope without getting off track. The alien menace grows, and — as the film’s title lets on — Brynn is entirely on her own since her neighbors (the police included) won’t lift a finger to help out. At its best, the action mirrors the most intense moments of Steven Spielberg’s 2005 adaptation of War of the Worlds, turning a normal home into a besieged extraterrestrial war zone. There’s even a touch of Home Alone.

The movie also does a great job of maintaining its mystery. The aliens are never explained in great detail; in fact, there’s hardly any dialogue in the film at all. The story is conveyed cleverly through the world itself, along with Dever’s excellent performance. Similarly, the other big secret — why everyone hates Brynn — is only hinted at until the very end. While it never strays too far from its initial concept, No One Will Save You still manages to keep its twists hard to predict. It’s best going in knowing as little as possible.

Now, this is a made-for-streaming movie, and there are a few points where that’s obvious. That mostly comes down to the CG and special effects; the creature designs are cool, a mix of classic aliens and Slenderman, but the final product looks unrealistic, lacking the kind of detail that makes it fit in with an otherwise real-world setting. This is especially true the few times you get an up-close look at an alien. Something just looks off. It’s like the tech can’t keep up with the ideas of the artists.

That said, No One Will Save You is a delightful surprise, and it comes just in time for spooky season. It’s a tight, focused thriller with a unique concept that it continues to build on. The ending is a little, well, odd, but the ride to get to it is delightfully intense.

No One Will Save You is streaming now on Hulu in the US and on Star Plus and Disney Plus elsewhere.