Some people might feel too unsettled to find the movie really pleasurable. Serious horror fans will rejoice, though, at this uncompromising big-budget creepfest, a slice of white-bread Americana soaked in blood.

The story of small-town paranoia and fear of the unknown comes from Stephen King (carrying strong echoes of the classic "Twilight Zone" episode "The Monsters are Due on Maple Street"). Writer/director Frank Darabont (who did King proud in "The Shawshank Redemption" and "The Green Mile") sets the eerie mood masterfully.

After a thunderstorm interrupts the utilities in a normal, sedate Maine village, dozens of residents head to the supermarket for supplies. Emergency vehicles race by, sirens screaming, as a blinding blanket of fog rolls up. The earth shudders. When visibility reaches zero a bloody, terrified man bursts in, shouting that some "thing" in the mist killed his friend.

Fear and distrust take root in the alarmed group, and as the evidence mounts that there is something dangerous outside, imaginations run wild. It's pollution from the chemical plant. It's the hush-hush Arrowhead Project at the military base. It's the End of Days.

When an attempt to clear the external exhaust pipe for the store's generator goes horribly wrong, the situation begins to spiral into chaos and mayhem. Drayton appeals to the crowd's reason to protect his young son. Ollie (Toby Jones), the meek-seeming store manager with a surprisingly hardy survivalist streak, thinks that's futile. "We're insane as a species," he says; fear is all that's needed to short-circuit reason. Mrs. Carmody, who sees the disaster as a calling to lead the community to God, convinces a faction of the fearful mob that only a human sacrifice will remove the mist.

The film builds tension like an ever-tightening clamp, allowing us to imagine the monstrosities in the mist before giving us any visual evidence. Through the first hour, most of the story's suspense flows from the unpredictable ways the townspeople will react to their situation.

The casting was crucial, and by using mostly unfamiliar faces, Darabont keeps us off balance, uncertain of what to expect. None of the actors comes with the implied life insurance policy that marquee stars carry in these situations. He puts aside the polished technique of his earlier King adaptations, shooting guerilla-fashion with a nervously darting camera.