Why do I keep watching scary movies by myself? Even when they’re stupid, I want to surround myself with guard dogs, and when they’re actually scary, I almost lose my mind.

Which is exactly what happened when I was watching The Mist, the latest Stephen King adaptation from Frank Darabont (The Green Mile, The Shawshank Redemption.) The movie flopped when it came out last fall, but it got decent reviews. So last Friday, when Andrew was spending the evening with his family, I decided I’d rent ‘er up and see if I got spooked.

And let me point out: The Mist is about creepy bug-aliens lurking in the fog that envelops a New England town, and I watched it in the middle of a thunderstorm, with nothing handy for protection except my double-thick fleece blanket and the paltry little chain on my apartment door. Already, I was behaving like a fool. Any monster could’ve snapped that chain with a snap of its bug-alien jaws.

And it turns out the movie is really, really scary.

(Keep reading if you like, but be aware: I will give away every major plot point of the film.)

Kind of like 28 Days Later, The Mist is scary in two ways, both viscerally and psychologically. The first half uses your basic scare tactics: Lots of silence and tense expressions as people start wondering if they should just stay in a local grocery store, or wander out into the fog and risk screaming like that woman did a few minutes ago. Or wait… was she screaming? Was she? No! We were hearing things! Let’s go to our trucks and … AAAAH!

Holy crap! Is that a bloody pair of legs with no body attached? Is that a bug-alien slamming into the window? Are those the lights going out?

Is that Mark, pausing the movie while he double-checks the chain lock, closes all the blinds, and grabs a knife?

Well… yes. As I said, it’s a scary movie.

But then comes the second half, when the people in the grocery store break into factions: One is led by David, a rational do-gooder played by Thomas Jane, and the other is fronted by Mrs. Carmody, a nutjob religious fanatic played by the ever-amazing Marcia Gay Harden. This section is scary for entirely different reasons.

Here’s the thing: Mrs. Carmody keeps insisting that the bug-aliens are a vengeance delivered by the angry, Old Testament God. She convinces most of the folks in the grocery store that she’s right, and that they should sacrifice sinners in order to appease their wrathful maker.

In one terrifying scene, she insists that they kill David’s nine year-old son, Billy. That’s when David’s small band of clear-thinking heroes execute Mrs. Carmody and take their chances in the mist.

Obvious choice, right? Because it seems like the movie is making that classic horror statement about humans being worse than any monster. (That’s what 28 Days Later says when those soldiers go nutso.)

But in the controversial final scene, David’s car runs out of gas before he and his friends can escape. Sitting in the mist, they assume they have no options, so David uses the last four bullets in his gun to kill the other four people in his car. Including his little boy.

And then soldiers march through the fog. The sun comes out. We see trucks full of rescued civilians. If he had waited just a little bit longer—if he had kept a shred of hope—David’s friends and David’s child would be alive. Instead, he has to sit on the asphalt, aware of what he’s done.

For a liberal audience member like me, this movie asks a terrible question: What if the fanatics are right?

The entire film asks us to side with David. He always makes heroic choices, and he often risks his own life to save others. He refuses to participate in the ritual sacrifice of a soldier, trying instead to talk down the grocery store mob.

And yet it’s his rational mind that leads to his doom. As Darabont notes in the film’s commentary, he even ends up sacrificing his son, just like Mrs. Carmody demanded. And even though she dies, there’s plenty of reason to believe that Mrs. Carmody’s actions saved dozens of lives. By converting them to her faith, she kept them breathing. (In an early scene, we even see her praying to God that He let her bring new lambs to His flock. That, she says, will make her life count. And arguably, her prayers are answered.)

Also telling: When the bug-aliens first invade the store, one of them stings and kills a teenage girl. In horror movie terms, she’s done everything right, meaning that she specifically rejects the sexual advances of a boy she likes. But she still dies. Later, a similar bug lands on Mrs. Carmody, who prays (successfully) to be spared. Is her belief in an Old Testament God (her term) what saves her? Is an adherence to conservative morality the thing that can save us?

The film constantly references the old ways. David himself hand-paints movie posters, and he bemoans the death of his art to computerized graphics. Meanwhile, a falling tree destroys his neighbor’s classic car, an irreplaceable beaut. Does the end of old things portend disaster?

I don’t think Darabont—who wrote the final scene himself—is arguing that we should get Old Time Religion and start praying for forgiveness. I think the religion in the film is just a contemporary framework for a much deeper, more persistent cultural fear—the fear that our moral compass is wrong.

Because really, wouldn’t most of us rather be David? Wouldn’t we rather save a child than sacrifice it? Wouldn’t we rather be individuals than get sucked into Mrs. Carmody’s hive mind?

At the very least, I would rather be David, and I think plenty of people feel like I do. He’s a classic iteration of a hero.

And this movie shows our hero making a terrible choice for all the right reasons. We shudder at what he’s done, but we see the nobility in it. He’s trying to give these people a good death instead of a monstrous one.

Then we learn that David’s good impulses are exactly what make him fail. If he had been pious and fearful and compliant, his son would be alive. He wouldn’t be a murderer.

Extrapolated to everyday life, the implications of that conclusion are far more terrifying than any alien. What if our so-called “upright choices” are a mistake? What if the things we call evil are righteous after all? Every one of us, regardless of our religious or political beliefs, knows how it feels to look at something we believe in and consider the possibility that we’re misguided.

If we realize we are mistaken, we’re left with unsettling options for our lives–radical change, obsolescence, or self-delusion. That’s a scary thing to think about.

And because it raises that dense, sophisticated conundrum, The Mist is one of the most affecting horror films I have ever seen.