Kate Hudson creeps towards the shaking door in classic horror-movie style and slowly reaches toward it. A sound startles her, and she jumps. The audience, however, isn’t so alarmed. In “The Skeleton Key,” which opens this weekend, the usually trustworthy musical cues to “jump” simply leave us dangling.

And yet. Most disappointed audiences don’t get to see a sample of “what might have been.” We, however, are treated to a demonstration of the dream deferred when director Iain Softley throws us a bone in the final chapter of the film and brings us to the edge of our seats. He’s no Hitchcock, but this last third or so leaves us with a fast pulse and an uneasy mind to take home—which is all we can really ask of the horror genre.

“The Skeleton Key,” set in the beautiful bayous of Louisiana, offers cinematographic treats for the southernly-inclined. It will at least keep the attention of those who are not entranced by the other object of the camera’s gaze, Hudson. While it is natural to play up the sexuality of the female heroine in a screamfest, the length this film goes through to present all the lovely parts of the Hawn-spawn are beyond excess. While the cute little black dress she dons to meet an invalid she will take care of could be considered an interview outfit, the low-rise jeans, fancy belt, and itty-bitty, stomach-revealing top aren’t the choice I would make for giving an ill, old man a sponge bath.

The plot is simple. Hudson, a nursing student with a guilt complex over not being there for her dying father, moves in with Mr. and Mrs. Devereaux, played by John Hurt and Gena Rowlands. In this house with many doors and no mirrors, she is handed the “skeleton key,” the one key that will unlock all the doors (a symbolism carried to extremes throughout the film). When she has trouble unlocking the door in the attic, she starts to suspect that something is fishy, which leads her down the trail to hoodoo—a cousin of voodoo practiced in Louisiana. And there is the necessary semi-love interest in the form of lawyer Luke, played in true John Grisham style with the twang and the charm of Peter Sarsgaard.

It’s hard to pinpoint exactly how Softley turns around the terror clichés of creaking chairs and creepy old people into something that is actually shriek-worthy. Much of it may come from falling victim to the movie’s own theories. In regard to the hoodoo, we are warned that it “can’t hurt you if you don’t believe.” Eventually, writer Ehren Kruger (“The Ring”) builds up enough back story—combined with some freaky black-and-white film work—to get us believing for a moment, too. If this mirrored effect is intentional, it is a brief appearance of genius. If not, at least it gets the blood pumping.

When not tossing and turning through dark stormy nights in pretty lacy underwear and barely-there white tees, Hudson decently delivers the stale dialogue handed her. About to enter a suspicious shop with her best friend, “Jill the Thrill” (Joy Bryant), she taunts, “You’re scared? ‘Jill the Thrill’ is scared.”

Hudson isn’t a bad actress—we’ll leave that to “Jill the Thrill”—but she does little to transcend the trite. In this film, acting deftness seems to increase with age. Rowlands as Violet Devereaux, the overbearing wife, is convincingly crazy and generally splendid. Hurt may not have many lines as the stroke-burdened husband, Ben Devereaux, but his haunting stare and stark showing of sickness are the scariest parts of the early minutes.

The charms that are performed on us, while good, are only sleight of hand—and only partially redeem a plodding movie. Even the spells at the end are occasionally flawed as horrors miraculously reappear to an almost-comical effect. Many will be seduced to sleep without ever realizing that “The Skeleton Key” actually has a little something to offer. This little something is still not quite enough for moviegoers to curse themselves with a $10 ticket, but for those who keep watching, it will conjure goose bumps in the end.

—Staff writer Margaret M. Rossman can be reached at rossman@fas.harvard.edu.