On a star-filled night, widower and homeless man Thomas Jacobs (Michael Paré) finds shelter for the night when he stumbles across a vast two-story house with the lights on and an inviting open front door. He strolls in, thinking he just caught a lucky break, and it would appear for a while as though he did. Soon enough, Thomas realizes that the house won't let him leave, as all of its doors are locked and its windows cannot be opened or broken.