In “The Skeleton Key,” Kate Hudson (“Almost Famous”) plays a hospice nurse who does what frightened white people in movies usually do when they find out they're living in a haunted house: She stays.

Granted, you expect a woman who changes adult diapers for a living to have an underdeveloped flight response, but get a clue already.

Hudson's brush with the supernatural makes for a tolerable sort of nonsense in “The Skeleton Key.” While spooky in spots with its milieu of swampy decay, evil incantations and voodoo wickedness, it's an unremarkable achievement destined to join the likes of “Gothika,” “Stigmata” and “The Forgotten” on that ever-growing fresco of indistinguishably mediocre femme-themed horror movies.

Hudson plays Caroline Ellis, an ex-rock groupie from Hoboken, N.J., who quits her job at a New Orleans hospice center to care for stroke victim Ben Devereaux (John Hurt) in the vast, drafty mansion he shares with his wife, Violet (Gena Rowlands). Perched on the edge of a swamp, the house has a sordid history (something to do with lynchings and murderous spouses) and an attic full of “hoodoo” paraphernalia that intrepid Caroline (armed with the mansion's master key) discovers while investigating the cause of Ben's stroke.

Ravaged by guilt for abandoning her own invalid father — a conceit presented without much conviction by Hudson or director Iain Softley (“K-Pax”) — Caroline becomes fiercely protective of Ben when she suspects that Violet is using her black magic skills to poison him (probably with a “remedy” extracted from her garden). Hudson's scenes with Hurt are genuinely unnerving; with his burning, rheumatic eyes, the “Alien” actor is brilliantly effective as a mute witness to some unspeakable supernatural perversion.

Suspecting foul play, Caroline turns to the family's kindly estate lawyer (Peter Sarsgaard from “Kinsey”), paving the way for a preposterous bait-and-switch contraption that feels like something Rod Serling might have whipped up after reading a V.C. Andrews book. Director Softley seems to find it particularly painful, impatiently fast-forwarding the images during key moments of intrigue, like he can't wait to get it over and done with.

‘The Skeleton Key’
Starring: Kate Hudson, Gena Rowlands, John Hurt, Peter Sarsgaard
Rating: PG-13 (violence, disturbing images, some partial nudity and thematic material) Running time: 104 minutes
Playing: Opens Friday in Valley theaters