Sally Hurst is a lonely and withdrawn girl, who comes to Rhode Island to live with her father and his girlfriend in an ancient nineteenth century castle. While exploring the old building she finds a secret basement that no one has entered since the mansion’s architect disappeared more than a century ago. Unwillingly, Sally releases the ancient creature of darkness, which tries to drag her into the abyss hidden under the floor. Now she has to convince Alex and Kim that this is not her imagination until the creature swallows them all.