Welcome to Cheat Sheet, our brief breakdown-style reviews of festival films, VR previews, and other special event releases. This review was first posted out of Fantastic Fest in Austin, Texas. It is being republished to coincide with the film’s release on Amazon Prime Video.

One of the serious advantages to smaller, indie speculative-fiction movies is that you generally don’t know what you’re getting up front. In today’s anticipation culture, websites often drool over every possible detail and reveal about the bigger nerd-friendly properties. It’s easy to walk into a big movie feeling like you already know all the major beats, because they’ve been discussed to death online in “Everything we know about this movie” articles, and “Let’s pick apart this trailer frame-by-frame” videos.

And then along comes something unheralded, under-the-radar, and authentically strange, like the Canadian movie Radius. Suddenly the audience is on a fast-paced trip into the unknown, with no idea where this premise could possibly lead. And Radius, the latest collaboration between married writer-director team Caroline Labrèche and Steeve Léonard, does start with an unbeatable premise that feels like a solid Stephen King horror story. A man wakes up in a wrecked truck and goes looking for help. His memory is completely gone. He can’t even remember his name. And slowly, he starts to realize that anything living that comes within a certain radius of him instantly drops dead.

(Warning for the spoiler-averse: this trailer gives away some things that are better discovered by watching the film.)

What’s the genre?

Small-scale indie science fiction thriller. Think something between Safety Not Guaranteed and Colossal.

What’s it about?

Liam (Diego Klattenhoff, from Homeland and The Blacklist) has no memories after his accident. All he knows is that he’s creating a zone of instant death. Then a woman, also with no memories, comes to the shed where he’s hiding, and introduces herself as Jane Doe. Jane (Charlotte Sullivan, of Chicago Fire and Rookie Blue) has no idea how she knows him, and he has no idea how she can approach him and survive. The rest of the story unfolds from there, as they start piecing together their past and trying to figure out their future.

What’s it really about?

Labrèche and Léonard delve into a couple of interesting ideas here. One is how much loyalty we owe the past. Much like the Canadian science fiction series Dark Matter, Radius explores how much personality and predilections are tied to experience and memory, and whether people who don’t remember their own history have a duty to respect it and connect to it. This isn’t a particularly deep theme in this case: Radius raises the questions, but doesn’t have answers. But it’s a worthwhile thought experiment and conversation starter.

And the filmmakers also take an interest in the question of culpability. How much blame can we take for actions we can’t remember? And how much blame should we take for things we can’t help doing? Given the death toll around Liam, is he a murderer or a victim? When he can’t keep people from approaching him, is he responsible for their deaths, or are they? How much does he owe a society that can’t and won’t leave him alone?

Is it good?

Radius is certainly rough around the edges. It’s the kind of film where the limited budget and tight shooting schedule show through, and the acting can be a little erratic. Klattenhoff and Sullivan are at their strongest during the film’s faster-paced action sequences, where they bring across the desperation of their situation. But they’re both guilty of occasionally falling into a flat, strident affect that’s more suitable to a TV crime drama than a theatrical film. Some of the eventual reveals seem melodramatic, even soap-operatic. The film’s final moments are rushed, and the ending is startlingly abrupt, with no time for reflection.

All that falls away during the jaw-dropping moments when new pieces fall into place and Radius reveals where it’s going next. Like other amnesia-based films, from terrific examples like Memento to bottom-of-the-barrel stuff like Unknown, Radius is a puzzle story built around a series of reveals. The script is tight and propulsive; the writer-directors have a talent for not over-explaining the implications of each development, and for giving the audience space to figure things out for themselves. That makes the developments hit harder and feel smarter. Radius is a high-concept movie from start to finish, and it relies on surprises to keep the story moving. One of its biggest strengths is the way it keeps those surprises coming, rather than spending its narrative currency early and then spending the rest of its runtime on fallout.

The film’s pacing is also a major boon. Léonard and Labrèche time those surprises in a way that builds anticipation and dread by letting viewers stay ahead of the characters. When Liam first starts encountering the white-eyed, limp corpses of the people his power has killed, he initially doesn’t understand, and assumes he’s entered a plague zone. He covers his mouth with cloth and stumbles forward toward the next hapless victim he’s about to create. The audience knows what’s coming, and can cringe in sympathy, waiting for it to happen. The filmmakers play with this dynamic throughout the film, leading the audience along just enough. Radius is an experience in anticipation and tension as much as it is a linear story.

What should it be rated?

In spite of the body count and some grim, heart-in-mouth action situations, it’s free of sex, gore, and all sorts of other stuff that merits content warnings these days. But kids aren’t likely to get much out of it. Call it PG-13 just to keep yelling children out of the theater.

How can I actually watch it?

Radius is available on VOD services (iTunes, Amazon, Google Play, etc.) and was recently added to Amazon Prime Video as a free-for-subscribers film.