Caroline Ellis (KATE HUDSON) is a young hospice worker who wants to go to nursing school and get a job where she can actually help people. Accordingly, and against the advice of her friend Jill (JOY BRYANT), she takes a job outside her New Orleans home where she'll help Violet Devereaux (GENA ROWLANDS) take care of her ailing husband, Ben (JOHN HURT). It seems he's suffered a stroke that's left him speechless and limited to bed or wheelchairs and he reportedly doesn't have much time left. When she arrives, she meets the family's estate lawyer Luke Marshall (PETER SARSGAARD) who fills in all of the details, including that Violet is old school southern, and when the latter meets Caroline, she's concerned that the helper won't understand the house.
Caroline soon realizes what she means when she spots lines of red dust in front of doors and notes that their are no mirrors anywhere in the house. Then there's the matter of the attic where Ben reportedly had his stroke. Despite Violet giving her a skeleton key that supposedly will open every door in the house, Caroline discovers that it won't for a secondary attic door that's suspiciously hidden. When she asks Violet about it, she says it's never been open, but that only further arouses Caroline's curiosity.
With the discovery that the room was once home to the house's former servants, Papa Justify (RONALD MCCALL) and Mama Cecile (JERYL PRESCOTT SALES) who delved in the practice of hoodoo, Caroline soon realizes that something evil may be lurking in the house. With time running out and worrying about Ben's safety, Caroline learns what she can about black magic and the history of the house.