Sally Hurst is going to Rhode Island to live with her father, Alex, and his new girlfriend Kim in the nineteenth-century mansion they are restoring, but while exploring the estate, Sally finds a hidden basement and accidentally lets loose a race of ancient, dark-dwelling creatures who conspire to drag her down into the mysterious house's bottomless depths, and before the evil lurking in the dark consumes them all, Sally must convince Alex and Kim that it is not a fantasy.

Title and credits from container. Originally released as a motion picture in 2011. Based on the teleplay of 1973 made-for-TV movie by Nigel McKeand. Includes special features.