Steven Price is an amusement park mogul who delights in scaring the wits out of those who choose to ride his new attractions. His wife, Evelyn, seems to have had enough of him, but nonetheless wants him to throw her a birthday party at the long-closed Vannacutt Psychiatric Hospital for the Criminally Insane!

Sixty years previous, the head doctor performed unspeakable acts on the inmates until they revolted and they all burned to death. Now empty, Evelyn thinks it will be a fun place for a party. Steven, who distrusts his wife almost as much as she detests him, has set up a number of surprises in the building, and has substituted his wife's guest list with a different set of names. Unbeknownst to him, the list has been altered yet again, resulting in the arrival of a group unknown to either of the Prices. Surprised but undeterred, Steven announces not only that the building is reportedly haunted but that he'll pay anyone who can spend the entire night there - without dying or running away in fright - one million dollars each.

Not that they can run away, as the building's security system closes off any and all exits, doors and windows, effectively sealing everyone inside. From that point on and as the night progresses, the unwillingly assembled group attempts to get out while trying to figure out whether the eerie and seemingly lethal occurrences within the house are just Price's trickery or is a result of the building being haunted.