The Night They Returned (2004)

Confined to a cell in a mental asylum, young Jessica has a tale to tell, if the doctors will listen. See, Jessica comes from a family a bit more dysfunctional than most. Her sexy sisters Brenda and Tawny would frequently tie her up in her bedroom for her own safety, they claimed. Maybe, but more likely to prevent her from interfering in their favorite pastime. Seems the two sisters have a habit of seducing hapless males into returning to their secluded backwoods cabin, only to be trussed up, brutally butchered and snacked on! But dad's in the house, why won't he do something about these ghoulish shenanigans? Oh, that's right. He's dead! Not that that stops the sisters from doting on dear old dad, or at least what's left of him. Once done with their unfortunate victims, the girls have been tossing their chopped-up remains in a nearby creek. But someone else has been depositing their dirty secrets their too. The sisters don't make much of the discarded container of biohazardous waste they find there until the toxic sauce has an unexpected effect on the body parts at the bottom of the creek!