This Southern Gothic potboiler from Iain Softley actually admits to being about a deep-fried form of Louisiana folk magic called hoodoo, and the term fits wonderfully with the fact that the movie is utter hooey. Basically a damsel-in-distress outing set in the steamy bayou country, where sudden storms always pop up at the most convenient moments to add lightning flashes and claps of thunder to the proceedings, the movie suffers not only from its hoary plot but from rampant miscasting and a sorry tendency to camp things up without apparently realizing it. By the end, it’s become risible–unintentionally, of course.

Kate Hudson stars as Caroline Ellis, a nursing student unfulfilled by her job holding the hands of dying, forgotten-by-their-families patients in a New Orleans hospice. Seeking something more rewarding, she impetuously accepts a live-in position caring for Ben Devereaux (John Hurt), a terminal stroke victim, in his remote mansion. The only other people on hand will be Ben’s controlling wife Violet (Gena Rowlands), an ostensibly concerned but strangely sinister presence, and the couple’s estate lawyer Luke (Peter Sarsgaard), who becomes a sort of bemused confidant to Caroline, acting as a surrogate for Jill (Joy Bryant), the predictably sassy African-American roommate she’s left behind in the Big Easy.

Let it be said from the first that Caroline seems to be just about the worst nurse-attendant one could imagine. She proves singularly inept at watching over her patient, whom at one point she permits to crawl onto a second-story roof and fall to the ground (luckily it’s just been raining again, so the mud softens the collision) and at another literally causes to have a seizure just to fulfill her curiosity. (She also insists on wearing the most provocative possible duds to serve as eye candy for the audience even though they hardly fit with her job or the setting.) Instead Caroline becomes a new Nancy Drew, spending her time ignoring Ben but investigating the house’s deep, dark secrets–which, as it turns out, involve the lynching long ago of two servants named Papa Justify and Mama Cynthia, who also happened to be powerful practitioners of that hoodoo stuff; and she becomes convinced that Violet is in league with the evil forces lingering from the old days and is the cause of Ben’s condition. One doesn’t want to reveal where the plot is going, but did you ever see “Spellbinder”?

“The Skeleton Key” is one of those modern ghost stories that embraces all the genre conventions without recognizing how hackneyed and laughable they’ve become. The look of the picture has obviously been given a good deal of attention by Softley, production designer John Beard, art director Drew Boughton, set designers Julia Levine and Mick Cukurs, set decorator Beauchamp Fontaine and cinematographer Dan Mindel. But what good is all the dank, sultry atmosphere in the world if most of the running-time is taken up by scenes of people–mostly Hudson, of course, but sometimes Rowlands, too–stumbling around musty rooms and dank hallways, often calling out somebody else’s name (the oldest cliche in horror filmdom)? And by those cheap thrill moments when a character is startled by the sudden appearance of another person (always accompanied by a sudden burst of Edward Shearmur’s formulaic score)? Ehren Kruger’s clumsy, derivative script has other elements, of course, but they don’t help. Certainly the worst of his inventions is a big, drag-out battle between Caroline and Violet that has both women thrashing about ferociously in full cat-fight mode–an episode that’s more likely to leave you shaking with laughter than with fright. It certainly doesn’t help that neither woman seems at all comfortable in her role. Hudson comes across as petulant and inept rather than sympathetic, and so one cares little when a macabre twist involving her is sprung at the end. As for Rowlands, she’s never remotely convincing as a Louisiana grande dame, and when she throws herself into full Bette Davis “Baby Jane” mode toward the close, the result is simply embarrassing. Sarsgaard is slick in a role that demands little, and Hurt manages to look properly catatonic and terrified at the necessary points, but the males here are playing second fiddle to a distaff act that’s less than top-drawer.

In sum, all the special effects and gotcha surprises can’t put any meat on the tired old narrative bones of “The Skeleton Key.” As Mrs. Devereaux says after recounting her home’s checkered past to Caroline, “It was a terrible thing, terrible.” The same thought may occur to you as you leave the theatre.